Re: mainline build failure for x86_64 allmodconfig with clang
On Fri, Aug 26, 2022 at 10:31:34AM -0400, Alex Deucher wrote: > On Thu, Aug 25, 2022 at 6:34 PM Nathan Chancellor wrote: > > > > Hi AMD folks, > > > > Top posting because it might not have been obvious but I was looking for > > your feedback on this message (which can be viewed on lore.kernel.org if > > you do not have the original [1]) so that we can try to get this fixed > > in some way for 6.0/6.1. If my approach is not welcome, please consider > > suggesting another one or looking to see if this is something you all > > could look into. > > The patch looks good to me. I was hoping Harry or Rodrigo could > comment more since they are more familiar with this code and trying to > keep it in sync with what we get from the hardware teams. Thanks a lot for the input! That patch was broken but I have polished it and a few other patches up and sent them along for review: https://lore.kernel.org/20220830203409.3491379-1-nat...@kernel.org/ I did not CC everyone from this thread but it is on lore if others want to comment on it. Hopefully we can get this all sorted out for 6.0 final. Cheers, Nathan > > [1]: https://lore.kernel.org/Yv5h0rb3AgTZLVJv@dev-arch.thelio-3990X/ > > > > Cheers, > > Nathan > > > > On Thu, Aug 18, 2022 at 08:59:14AM -0700, Nathan Chancellor wrote: > > > Hi Arnd, > > > > > > Doubling back around to this now since I think this is the only thing > > > breaking x86_64 allmodconfig with clang 11 through 15. > > > > > > On Fri, Aug 05, 2022 at 09:32:13PM +0200, Arnd Bergmann wrote: > > > > On Fri, Aug 5, 2022 at 8:02 PM Nathan Chancellor > > > > wrote: > > > > > On Fri, Aug 05, 2022 at 06:16:45PM +0200, Arnd Bergmann wrote: > > > > > > On Fri, Aug 5, 2022 at 5:32 PM Harry Wentland > > > > > > wrote: > > > > > > While splitting out sub-functions can help reduce the maximum stack > > > > > > usage, it seems that in this case it makes the actual problem worse: > > > > > > I see 2168 bytes for the combined > > > > > > dml32_ModeSupportAndSystemConfigurationFull(), but marking > > > > > > mode_support_configuration() as noinline gives me 1992 bytes > > > > > > for the outer function plus 384 bytes for the inner one. So it does > > > > > > avoid the warning (barely), but not the problem that the warning > > > > > > tries > > > > > > to point out. > > > > > > > > > > I haven't had a chance to take a look at splitting things up yet, > > > > > would > > > > > you recommend a different approach? > > > > > > > > Splitting up large functions can help when you have large local > > > > variables > > > > that are used in different parts of the function, and the split gets the > > > > compiler to reuse stack locations. > > > > > > > > I think in this particular function, the problem isn't actually local > > > > variables > > > > but either pushing variables on the stack for argument passing, > > > > or something that causes the compiler to run out of registers so it > > > > has to spill registers to the stack. > > > > > > > > In either case, one has to actually look at the generated output > > > > and then try to rearrange the codes so this does not happen. > > > > > > > > One thing to try would be to condense a function call like > > > > > > > > > > > > dml32_CalculateWatermarksMALLUseAndDRAMSpeedChangeSupport( > > > > > > > > >dummy_vars.dml32_CalculateWatermarksMALLUseAndDRAMSpeedChangeSupport, > > > > mode_lib->vba.USRRetrainingRequiredFinal, > > > > mode_lib->vba.UsesMALLForPStateChange, > > > > > > > > mode_lib->vba.PrefetchModePerState[mode_lib->vba.VoltageLevel][mode_lib->vba.maxMpcComb], > > > > mode_lib->vba.NumberOfActiveSurfaces, > > > > mode_lib->vba.MaxLineBufferLines, > > > > mode_lib->vba.LineBufferSizeFinal, > > > > mode_lib->vba.WritebackInterfaceBufferSize, > > > > mode_lib->vba.DCFCLK, > > > > mode_lib->vba.ReturnBW, > > > > mode_lib->vba.SynchronizeTimingsFinal, > > > > > > > > mode_lib->vba.SynchronizeDRRDisplaysForUCLKPStateChangeFinal, > > > > mode_lib->vba.DRRDisplay, > > > > v->dpte_group_bytes, > > > > v->meta_row_height, > > > > v->meta_row_height_chroma, > > > > > > > > v->dummy_vars.DISPCLKDPPCLKDCFCLKDeepSleepPrefetchParametersWatermarksAndPerformanceCalculation.mmSOCParameters, > > > > mode_lib->vba.WritebackChunkSize, > > > > mode_lib->vba.SOCCLK, > > > > v->DCFCLKDeepSleep, > > > > mode_lib->vba.DETBufferSizeY, > > > > mode_lib->vba.DETBufferSizeC, > > > > mode_lib->vba.SwathHeightY, > > > > mode_lib->vba.SwathHeightC, > > > >
Re: mainline build failure for x86_64 allmodconfig with clang
On Thu, Aug 25, 2022 at 6:34 PM Nathan Chancellor wrote: > > Hi AMD folks, > > Top posting because it might not have been obvious but I was looking for > your feedback on this message (which can be viewed on lore.kernel.org if > you do not have the original [1]) so that we can try to get this fixed > in some way for 6.0/6.1. If my approach is not welcome, please consider > suggesting another one or looking to see if this is something you all > could look into. The patch looks good to me. I was hoping Harry or Rodrigo could comment more since they are more familiar with this code and trying to keep it in sync with what we get from the hardware teams. Alex > > [1]: https://lore.kernel.org/Yv5h0rb3AgTZLVJv@dev-arch.thelio-3990X/ > > Cheers, > Nathan > > On Thu, Aug 18, 2022 at 08:59:14AM -0700, Nathan Chancellor wrote: > > Hi Arnd, > > > > Doubling back around to this now since I think this is the only thing > > breaking x86_64 allmodconfig with clang 11 through 15. > > > > On Fri, Aug 05, 2022 at 09:32:13PM +0200, Arnd Bergmann wrote: > > > On Fri, Aug 5, 2022 at 8:02 PM Nathan Chancellor > > > wrote: > > > > On Fri, Aug 05, 2022 at 06:16:45PM +0200, Arnd Bergmann wrote: > > > > > On Fri, Aug 5, 2022 at 5:32 PM Harry Wentland > > > > > wrote: > > > > > While splitting out sub-functions can help reduce the maximum stack > > > > > usage, it seems that in this case it makes the actual problem worse: > > > > > I see 2168 bytes for the combined > > > > > dml32_ModeSupportAndSystemConfigurationFull(), but marking > > > > > mode_support_configuration() as noinline gives me 1992 bytes > > > > > for the outer function plus 384 bytes for the inner one. So it does > > > > > avoid the warning (barely), but not the problem that the warning tries > > > > > to point out. > > > > > > > > I haven't had a chance to take a look at splitting things up yet, would > > > > you recommend a different approach? > > > > > > Splitting up large functions can help when you have large local variables > > > that are used in different parts of the function, and the split gets the > > > compiler to reuse stack locations. > > > > > > I think in this particular function, the problem isn't actually local > > > variables > > > but either pushing variables on the stack for argument passing, > > > or something that causes the compiler to run out of registers so it > > > has to spill registers to the stack. > > > > > > In either case, one has to actually look at the generated output > > > and then try to rearrange the codes so this does not happen. > > > > > > One thing to try would be to condense a function call like > > > > > > dml32_CalculateWatermarksMALLUseAndDRAMSpeedChangeSupport( > > > > > > >dummy_vars.dml32_CalculateWatermarksMALLUseAndDRAMSpeedChangeSupport, > > > mode_lib->vba.USRRetrainingRequiredFinal, > > > mode_lib->vba.UsesMALLForPStateChange, > > > > > > mode_lib->vba.PrefetchModePerState[mode_lib->vba.VoltageLevel][mode_lib->vba.maxMpcComb], > > > mode_lib->vba.NumberOfActiveSurfaces, > > > mode_lib->vba.MaxLineBufferLines, > > > mode_lib->vba.LineBufferSizeFinal, > > > mode_lib->vba.WritebackInterfaceBufferSize, > > > mode_lib->vba.DCFCLK, > > > mode_lib->vba.ReturnBW, > > > mode_lib->vba.SynchronizeTimingsFinal, > > > > > > mode_lib->vba.SynchronizeDRRDisplaysForUCLKPStateChangeFinal, > > > mode_lib->vba.DRRDisplay, > > > v->dpte_group_bytes, > > > v->meta_row_height, > > > v->meta_row_height_chroma, > > > > > > v->dummy_vars.DISPCLKDPPCLKDCFCLKDeepSleepPrefetchParametersWatermarksAndPerformanceCalculation.mmSOCParameters, > > > mode_lib->vba.WritebackChunkSize, > > > mode_lib->vba.SOCCLK, > > > v->DCFCLKDeepSleep, > > > mode_lib->vba.DETBufferSizeY, > > > mode_lib->vba.DETBufferSizeC, > > > mode_lib->vba.SwathHeightY, > > > mode_lib->vba.SwathHeightC, > > > mode_lib->vba.LBBitPerPixel, > > > v->SwathWidthY, > > > v->SwathWidthC, > > > mode_lib->vba.HRatio, > > > mode_lib->vba.HRatioChroma, > > > mode_lib->vba.vtaps, > > > mode_lib->vba.VTAPsChroma, > > > mode_lib->vba.VRatio, > > > mode_lib->vba.VRatioChroma, > > > mode_lib->vba.HTotal, > > > mode_lib->vba.VTotal, > > > mode_lib->vba.VActive, > > >
Re: mainline build failure for x86_64 allmodconfig with clang
Hi AMD folks, Top posting because it might not have been obvious but I was looking for your feedback on this message (which can be viewed on lore.kernel.org if you do not have the original [1]) so that we can try to get this fixed in some way for 6.0/6.1. If my approach is not welcome, please consider suggesting another one or looking to see if this is something you all could look into. [1]: https://lore.kernel.org/Yv5h0rb3AgTZLVJv@dev-arch.thelio-3990X/ Cheers, Nathan On Thu, Aug 18, 2022 at 08:59:14AM -0700, Nathan Chancellor wrote: > Hi Arnd, > > Doubling back around to this now since I think this is the only thing > breaking x86_64 allmodconfig with clang 11 through 15. > > On Fri, Aug 05, 2022 at 09:32:13PM +0200, Arnd Bergmann wrote: > > On Fri, Aug 5, 2022 at 8:02 PM Nathan Chancellor wrote: > > > On Fri, Aug 05, 2022 at 06:16:45PM +0200, Arnd Bergmann wrote: > > > > On Fri, Aug 5, 2022 at 5:32 PM Harry Wentland > > > > wrote: > > > > While splitting out sub-functions can help reduce the maximum stack > > > > usage, it seems that in this case it makes the actual problem worse: > > > > I see 2168 bytes for the combined > > > > dml32_ModeSupportAndSystemConfigurationFull(), but marking > > > > mode_support_configuration() as noinline gives me 1992 bytes > > > > for the outer function plus 384 bytes for the inner one. So it does > > > > avoid the warning (barely), but not the problem that the warning tries > > > > to point out. > > > > > > I haven't had a chance to take a look at splitting things up yet, would > > > you recommend a different approach? > > > > Splitting up large functions can help when you have large local variables > > that are used in different parts of the function, and the split gets the > > compiler to reuse stack locations. > > > > I think in this particular function, the problem isn't actually local > > variables > > but either pushing variables on the stack for argument passing, > > or something that causes the compiler to run out of registers so it > > has to spill registers to the stack. > > > > In either case, one has to actually look at the generated output > > and then try to rearrange the codes so this does not happen. > > > > One thing to try would be to condense a function call like > > > > dml32_CalculateWatermarksMALLUseAndDRAMSpeedChangeSupport( > > > > >dummy_vars.dml32_CalculateWatermarksMALLUseAndDRAMSpeedChangeSupport, > > mode_lib->vba.USRRetrainingRequiredFinal, > > mode_lib->vba.UsesMALLForPStateChange, > > > > mode_lib->vba.PrefetchModePerState[mode_lib->vba.VoltageLevel][mode_lib->vba.maxMpcComb], > > mode_lib->vba.NumberOfActiveSurfaces, > > mode_lib->vba.MaxLineBufferLines, > > mode_lib->vba.LineBufferSizeFinal, > > mode_lib->vba.WritebackInterfaceBufferSize, > > mode_lib->vba.DCFCLK, > > mode_lib->vba.ReturnBW, > > mode_lib->vba.SynchronizeTimingsFinal, > > > > mode_lib->vba.SynchronizeDRRDisplaysForUCLKPStateChangeFinal, > > mode_lib->vba.DRRDisplay, > > v->dpte_group_bytes, > > v->meta_row_height, > > v->meta_row_height_chroma, > > > > v->dummy_vars.DISPCLKDPPCLKDCFCLKDeepSleepPrefetchParametersWatermarksAndPerformanceCalculation.mmSOCParameters, > > mode_lib->vba.WritebackChunkSize, > > mode_lib->vba.SOCCLK, > > v->DCFCLKDeepSleep, > > mode_lib->vba.DETBufferSizeY, > > mode_lib->vba.DETBufferSizeC, > > mode_lib->vba.SwathHeightY, > > mode_lib->vba.SwathHeightC, > > mode_lib->vba.LBBitPerPixel, > > v->SwathWidthY, > > v->SwathWidthC, > > mode_lib->vba.HRatio, > > mode_lib->vba.HRatioChroma, > > mode_lib->vba.vtaps, > > mode_lib->vba.VTAPsChroma, > > mode_lib->vba.VRatio, > > mode_lib->vba.VRatioChroma, > > mode_lib->vba.HTotal, > > mode_lib->vba.VTotal, > > mode_lib->vba.VActive, > > mode_lib->vba.PixelClock, > > mode_lib->vba.BlendingAndTiming, > > /* more arguments */); > > > > into calling conventions that take a pointer to 'mode_lib->vba' and another > > one to 'v', so these are no longer passed on the stack individually. > > So I took a whack at reducing this function's number of parameters and > ended up with the attached patch. I basically just removed any > parameters that were
Re: mainline build failure for x86_64 allmodconfig with clang
Hi Arnd, Doubling back around to this now since I think this is the only thing breaking x86_64 allmodconfig with clang 11 through 15. On Fri, Aug 05, 2022 at 09:32:13PM +0200, Arnd Bergmann wrote: > On Fri, Aug 5, 2022 at 8:02 PM Nathan Chancellor wrote: > > On Fri, Aug 05, 2022 at 06:16:45PM +0200, Arnd Bergmann wrote: > > > On Fri, Aug 5, 2022 at 5:32 PM Harry Wentland > > > wrote: > > > While splitting out sub-functions can help reduce the maximum stack > > > usage, it seems that in this case it makes the actual problem worse: > > > I see 2168 bytes for the combined > > > dml32_ModeSupportAndSystemConfigurationFull(), but marking > > > mode_support_configuration() as noinline gives me 1992 bytes > > > for the outer function plus 384 bytes for the inner one. So it does > > > avoid the warning (barely), but not the problem that the warning tries > > > to point out. > > > > I haven't had a chance to take a look at splitting things up yet, would > > you recommend a different approach? > > Splitting up large functions can help when you have large local variables > that are used in different parts of the function, and the split gets the > compiler to reuse stack locations. > > I think in this particular function, the problem isn't actually local > variables > but either pushing variables on the stack for argument passing, > or something that causes the compiler to run out of registers so it > has to spill registers to the stack. > > In either case, one has to actually look at the generated output > and then try to rearrange the codes so this does not happen. > > One thing to try would be to condense a function call like > > dml32_CalculateWatermarksMALLUseAndDRAMSpeedChangeSupport( > > >dummy_vars.dml32_CalculateWatermarksMALLUseAndDRAMSpeedChangeSupport, > mode_lib->vba.USRRetrainingRequiredFinal, > mode_lib->vba.UsesMALLForPStateChange, > > mode_lib->vba.PrefetchModePerState[mode_lib->vba.VoltageLevel][mode_lib->vba.maxMpcComb], > mode_lib->vba.NumberOfActiveSurfaces, > mode_lib->vba.MaxLineBufferLines, > mode_lib->vba.LineBufferSizeFinal, > mode_lib->vba.WritebackInterfaceBufferSize, > mode_lib->vba.DCFCLK, > mode_lib->vba.ReturnBW, > mode_lib->vba.SynchronizeTimingsFinal, > > mode_lib->vba.SynchronizeDRRDisplaysForUCLKPStateChangeFinal, > mode_lib->vba.DRRDisplay, > v->dpte_group_bytes, > v->meta_row_height, > v->meta_row_height_chroma, > > v->dummy_vars.DISPCLKDPPCLKDCFCLKDeepSleepPrefetchParametersWatermarksAndPerformanceCalculation.mmSOCParameters, > mode_lib->vba.WritebackChunkSize, > mode_lib->vba.SOCCLK, > v->DCFCLKDeepSleep, > mode_lib->vba.DETBufferSizeY, > mode_lib->vba.DETBufferSizeC, > mode_lib->vba.SwathHeightY, > mode_lib->vba.SwathHeightC, > mode_lib->vba.LBBitPerPixel, > v->SwathWidthY, > v->SwathWidthC, > mode_lib->vba.HRatio, > mode_lib->vba.HRatioChroma, > mode_lib->vba.vtaps, > mode_lib->vba.VTAPsChroma, > mode_lib->vba.VRatio, > mode_lib->vba.VRatioChroma, > mode_lib->vba.HTotal, > mode_lib->vba.VTotal, > mode_lib->vba.VActive, > mode_lib->vba.PixelClock, > mode_lib->vba.BlendingAndTiming, > /* more arguments */); > > into calling conventions that take a pointer to 'mode_lib->vba' and another > one to 'v', so these are no longer passed on the stack individually. So I took a whack at reducing this function's number of parameters and ended up with the attached patch. I basically just removed any parameters that were identical between the two call sites and access them through the vba pointer, as you suggested. AMD folks, is this an acceptable approach? It didn't take a trivial amount of time so I want to make sure this is okay before I do it to more functions/files. Due to the potential size of these changes, I am a little weary of them going into 6.0; even though they should be a simple search and replace for the most part, it might be nice for them to have some decent soak time in -next. One solution would be to raise the warning limit for these files on 6.0 so that allmodconfig does not ship broken then reduce the limit for 6.1 once these patches have been applied. Additionally, I took a look at the stack usage across
Re: mainline build failure for x86_64 allmodconfig with clang
On Sun, Aug 7, 2022 at 10:36 AM David Laight wrote: > > Or just shoot the software engineer who thinks 100 arguments > is sane. :-) I suspect the issue is that it's not primarily a software engineer who wrote that code. Hardware people writing code are about as scary as software engineers with a soldering iron. Linus
RE: mainline build failure for x86_64 allmodconfig with clang
From: Arnd Bergmann > Sent: 05 August 2022 20:32 ... > One thing to try would be to condense a function call like > > dml32_CalculateWatermarksMALLUseAndDRAMSpeedChangeSupport( > ... > /* more arguments */); > > into calling conventions that take a pointer to 'mode_lib->vba' and another > one to 'v', so these are no longer passed on the stack individually. Or, if it is only called once (I can't find the source) force it to be inlined. Or just shoot the software engineer who thinks 100 arguments is sane. :-) David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
Re: mainline build failure for x86_64 allmodconfig with clang
On Fri, Aug 5, 2022 at 8:02 PM Nathan Chancellor wrote: > On Fri, Aug 05, 2022 at 06:16:45PM +0200, Arnd Bergmann wrote: > > On Fri, Aug 5, 2022 at 5:32 PM Harry Wentland > > wrote: > > While splitting out sub-functions can help reduce the maximum stack > > usage, it seems that in this case it makes the actual problem worse: > > I see 2168 bytes for the combined > > dml32_ModeSupportAndSystemConfigurationFull(), but marking > > mode_support_configuration() as noinline gives me 1992 bytes > > for the outer function plus 384 bytes for the inner one. So it does > > avoid the warning (barely), but not the problem that the warning tries > > to point out. > > I haven't had a chance to take a look at splitting things up yet, would > you recommend a different approach? Splitting up large functions can help when you have large local variables that are used in different parts of the function, and the split gets the compiler to reuse stack locations. I think in this particular function, the problem isn't actually local variables but either pushing variables on the stack for argument passing, or something that causes the compiler to run out of registers so it has to spill registers to the stack. In either case, one has to actually look at the generated output and then try to rearrange the codes so this does not happen. One thing to try would be to condense a function call like dml32_CalculateWatermarksMALLUseAndDRAMSpeedChangeSupport( >dummy_vars.dml32_CalculateWatermarksMALLUseAndDRAMSpeedChangeSupport, mode_lib->vba.USRRetrainingRequiredFinal, mode_lib->vba.UsesMALLForPStateChange, mode_lib->vba.PrefetchModePerState[mode_lib->vba.VoltageLevel][mode_lib->vba.maxMpcComb], mode_lib->vba.NumberOfActiveSurfaces, mode_lib->vba.MaxLineBufferLines, mode_lib->vba.LineBufferSizeFinal, mode_lib->vba.WritebackInterfaceBufferSize, mode_lib->vba.DCFCLK, mode_lib->vba.ReturnBW, mode_lib->vba.SynchronizeTimingsFinal, mode_lib->vba.SynchronizeDRRDisplaysForUCLKPStateChangeFinal, mode_lib->vba.DRRDisplay, v->dpte_group_bytes, v->meta_row_height, v->meta_row_height_chroma, v->dummy_vars.DISPCLKDPPCLKDCFCLKDeepSleepPrefetchParametersWatermarksAndPerformanceCalculation.mmSOCParameters, mode_lib->vba.WritebackChunkSize, mode_lib->vba.SOCCLK, v->DCFCLKDeepSleep, mode_lib->vba.DETBufferSizeY, mode_lib->vba.DETBufferSizeC, mode_lib->vba.SwathHeightY, mode_lib->vba.SwathHeightC, mode_lib->vba.LBBitPerPixel, v->SwathWidthY, v->SwathWidthC, mode_lib->vba.HRatio, mode_lib->vba.HRatioChroma, mode_lib->vba.vtaps, mode_lib->vba.VTAPsChroma, mode_lib->vba.VRatio, mode_lib->vba.VRatioChroma, mode_lib->vba.HTotal, mode_lib->vba.VTotal, mode_lib->vba.VActive, mode_lib->vba.PixelClock, mode_lib->vba.BlendingAndTiming, /* more arguments */); into calling conventions that take a pointer to 'mode_lib->vba' and another one to 'v', so these are no longer passed on the stack individually. Arnd
Re: mainline build failure for x86_64 allmodconfig with clang
On Fri, Aug 05, 2022 at 06:16:45PM +0200, Arnd Bergmann wrote:
> On Fri, Aug 5, 2022 at 5:32 PM Harry Wentland wrote:
> > > I do notice that these files build with a non-configurable
> > > -Wframe-large-than value:
> > >
> > > $ rg frame_warn_flag drivers/gpu/drm/amd/display/dc/dml/Makefile
> > > 54:frame_warn_flag := -Wframe-larger-than=2048
> >
> > Tbh, I was looking at the history and I can't find a good reason this
> > was added. It should be safe to drop this. I would much rather use
> > the CONFIG_FRAME_WARN value than override it.
> >
> > AFAIK most builds use 2048 by default anyways.
>
> I'm fairly sure this was done for 32-bit builds, which default to a lower
> warning limit of 1024 bytes and would otherwise run into this
> problem when 64-bit platforms don't. With the default warning limit,
> clang warns even more about an i386 build:
>
> display/dc/dml/dcn20/display_rq_dlg_calc_20.c:1549:6: error: stack
> frame size (1324) exceeds limit (1024) in 'dml20_rq_dlg_get_dlg_reg'
> display/dc/dml/dcn20/display_rq_dlg_calc_20v2.c:1550:6: error: stack
> frame size (1324) exceeds limit (1024) in 'dml20v2_rq_dlg_get_dlg_reg'
> display/dc/dml/dcn30/display_rq_dlg_calc_30.c:1742:6: error: stack
> frame size (1484) exceeds limit (1024) in 'dml30_rq_dlg_get_dlg_reg'
> display/dc/dml/dcn31/display_rq_dlg_calc_31.c:1571:6: error: stack
> frame size (1548) exceeds limit (1024) in 'dml31_rq_dlg_get_dlg_reg'
> display/dc/dml/dcn21/display_rq_dlg_calc_21.c:1657:6: error: stack
> frame size (1388) exceeds limit (1024) in 'dml21_rq_dlg_get_dlg_reg'
> display/dc/dml/dcn32/display_rq_dlg_calc_32.c:206:6: error: stack
> frame size (1276) exceeds limit (1024) in 'dml32_rq_dlg_get_dlg_reg'
> display/dc/dml/dcn31/display_mode_vba_31.c:2049:13: error: stack frame
> size (1468) exceeds limit (1024) in
> 'DISPCLKDPPCLKDCFCLKDeepSleepPrefetchParametersWatermarksAndPerformanceCalculation'
> display/dc/dml/dcn20/display_mode_vba_20v2.c:1145:13: error: stack
> frame size (1228) exceeds limit (1024) in
> 'dml20v2_DISPCLKDPPCLKDCFCLKDeepSleepPrefetchParametersWatermarksAndPerformanceCalculation'
> display/dc/dml/dcn20/display_mode_vba_20.c:1085:13: error: stack frame
> size (1340) exceeds limit (1024) in
> 'dml20_DISPCLKDPPCLKDCFCLKDeepSleepPrefetchParametersWatermarksAndPerformanceCalculation'
> display/dc/dml/dcn31/display_mode_vba_31.c:3908:6: error: stack frame
> size (1996) exceeds limit (1024) in
> 'dml31_ModeSupportAndSystemConfigurationFull'
> display/dc/dml/dcn21/display_mode_vba_21.c:1466:13: error: stack frame
> size (1308) exceeds limit (1024) in
> 'DISPCLKDPPCLKDCFCLKDeepSleepPrefetchParametersWatermarksAndPerformanceCalculation'
> display/dc/dml/dcn20/display_mode_vba_20v2.c:3393:6: error: stack
> frame size (1356) exceeds limit (1024) in
> 'dml20v2_ModeSupportAndSystemConfigurationFull'
> display/dc/dml/dcn20/display_mode_vba_20.c:3286:6: error: stack frame
> size (1468) exceeds limit (1024) in
> 'dml20_ModeSupportAndSystemConfigurationFull'
> display/dc/dml/dcn21/display_mode_vba_21.c:3518:6: error: stack frame
> size (1228) exceeds limit (1024) in
> 'dml21_ModeSupportAndSystemConfigurationFull'
> display/dc/dml/dcn30/display_mode_vba_30.c:1906:13: error: stack frame
> size (1436) exceeds limit (1024) in
> 'DISPCLKDPPCLKDCFCLKDeepSleepPrefetchParametersWatermarksAndPerformanceCalculation'
> display/dc/dml/dcn30/display_mode_vba_30.c:3596:6: error: stack frame
> size (2092) exceeds limit (1024) in
> 'dml30_ModeSupportAndSystemConfigurationFull'
> > > I do note that commit 1b54a0121dba ("drm/amd/display: Reduce stack size
> > > in the mode support function") did have a workaround for GCC. It appears
> > > clang will still inline mode_support_configuration(). If I mark it as
> > > 'noinline', the warning disappears in that file.
> >
> > That'd be the best quick fix. I guess if we split out functions to fix
> > stack usage we should mark them as 'noinline' in the future to avoid
> > agressive compiler optimizations.
>
> While splitting out sub-functions can help reduce the maximum stack
> usage, it seems that in this case it makes the actual problem worse:
> I see 2168 bytes for the combined
> dml32_ModeSupportAndSystemConfigurationFull(), but marking
> mode_support_configuration() as noinline gives me 1992 bytes
> for the outer function plus 384 bytes for the inner one. So it does
> avoid the warning (barely), but not the problem that the warning tries
> to point out.
I haven't had a chance to take a look at splitting things up yet, would
you recommend a different approach?
Cheers,
Nathan
Re: mainline build failure for x86_64 allmodconfig with clang
On Fri, Aug 5, 2022 at 5:32 PM Harry Wentland wrote:
> > I do notice that these files build with a non-configurable
> > -Wframe-large-than value:
> >
> > $ rg frame_warn_flag drivers/gpu/drm/amd/display/dc/dml/Makefile
> > 54:frame_warn_flag := -Wframe-larger-than=2048
>
> Tbh, I was looking at the history and I can't find a good reason this
> was added. It should be safe to drop this. I would much rather use
> the CONFIG_FRAME_WARN value than override it.
>
> AFAIK most builds use 2048 by default anyways.
I'm fairly sure this was done for 32-bit builds, which default to a lower
warning limit of 1024 bytes and would otherwise run into this
problem when 64-bit platforms don't. With the default warning limit,
clang warns even more about an i386 build:
display/dc/dml/dcn20/display_rq_dlg_calc_20.c:1549:6: error: stack
frame size (1324) exceeds limit (1024) in 'dml20_rq_dlg_get_dlg_reg'
display/dc/dml/dcn20/display_rq_dlg_calc_20v2.c:1550:6: error: stack
frame size (1324) exceeds limit (1024) in 'dml20v2_rq_dlg_get_dlg_reg'
display/dc/dml/dcn30/display_rq_dlg_calc_30.c:1742:6: error: stack
frame size (1484) exceeds limit (1024) in 'dml30_rq_dlg_get_dlg_reg'
display/dc/dml/dcn31/display_rq_dlg_calc_31.c:1571:6: error: stack
frame size (1548) exceeds limit (1024) in 'dml31_rq_dlg_get_dlg_reg'
display/dc/dml/dcn21/display_rq_dlg_calc_21.c:1657:6: error: stack
frame size (1388) exceeds limit (1024) in 'dml21_rq_dlg_get_dlg_reg'
display/dc/dml/dcn32/display_rq_dlg_calc_32.c:206:6: error: stack
frame size (1276) exceeds limit (1024) in 'dml32_rq_dlg_get_dlg_reg'
display/dc/dml/dcn31/display_mode_vba_31.c:2049:13: error: stack frame
size (1468) exceeds limit (1024) in
'DISPCLKDPPCLKDCFCLKDeepSleepPrefetchParametersWatermarksAndPerformanceCalculation'
display/dc/dml/dcn20/display_mode_vba_20v2.c:1145:13: error: stack
frame size (1228) exceeds limit (1024) in
'dml20v2_DISPCLKDPPCLKDCFCLKDeepSleepPrefetchParametersWatermarksAndPerformanceCalculation'
display/dc/dml/dcn20/display_mode_vba_20.c:1085:13: error: stack frame
size (1340) exceeds limit (1024) in
'dml20_DISPCLKDPPCLKDCFCLKDeepSleepPrefetchParametersWatermarksAndPerformanceCalculation'
display/dc/dml/dcn31/display_mode_vba_31.c:3908:6: error: stack frame
size (1996) exceeds limit (1024) in
'dml31_ModeSupportAndSystemConfigurationFull'
display/dc/dml/dcn21/display_mode_vba_21.c:1466:13: error: stack frame
size (1308) exceeds limit (1024) in
'DISPCLKDPPCLKDCFCLKDeepSleepPrefetchParametersWatermarksAndPerformanceCalculation'
display/dc/dml/dcn20/display_mode_vba_20v2.c:3393:6: error: stack
frame size (1356) exceeds limit (1024) in
'dml20v2_ModeSupportAndSystemConfigurationFull'
display/dc/dml/dcn20/display_mode_vba_20.c:3286:6: error: stack frame
size (1468) exceeds limit (1024) in
'dml20_ModeSupportAndSystemConfigurationFull'
display/dc/dml/dcn21/display_mode_vba_21.c:3518:6: error: stack frame
size (1228) exceeds limit (1024) in
'dml21_ModeSupportAndSystemConfigurationFull'
display/dc/dml/dcn30/display_mode_vba_30.c:1906:13: error: stack frame
size (1436) exceeds limit (1024) in
'DISPCLKDPPCLKDCFCLKDeepSleepPrefetchParametersWatermarksAndPerformanceCalculation'
display/dc/dml/dcn30/display_mode_vba_30.c:3596:6: error: stack frame
size (2092) exceeds limit (1024) in
'dml30_ModeSupportAndSystemConfigurationFull'
> > I do note that commit 1b54a0121dba ("drm/amd/display: Reduce stack size
> > in the mode support function") did have a workaround for GCC. It appears
> > clang will still inline mode_support_configuration(). If I mark it as
> > 'noinline', the warning disappears in that file.
>
> That'd be the best quick fix. I guess if we split out functions to fix
> stack usage we should mark them as 'noinline' in the future to avoid
> agressive compiler optimizations.
While splitting out sub-functions can help reduce the maximum stack
usage, it seems that in this case it makes the actual problem worse:
I see 2168 bytes for the combined
dml32_ModeSupportAndSystemConfigurationFull(), but marking
mode_support_configuration() as noinline gives me 1992 bytes
for the outer function plus 384 bytes for the inner one. So it does
avoid the warning (barely), but not the problem that the warning tries
to point out.
Arnd
Re: mainline build failure for x86_64 allmodconfig with clang
On 2022-08-04 16:43, Nathan Chancellor wrote:
> On Thu, Aug 04, 2022 at 09:24:41PM +0200, Arnd Bergmann wrote:
>> On Thu, Aug 4, 2022 at 8:52 PM Linus Torvalds
>> wrote:
>>>
>>> On Thu, Aug 4, 2022 at 11:37 AM Sudip Mukherjee (Codethink)
>>> wrote:cov_trace_cmp
git bisect points to 3876a8b5e241 ("drm/amd/display: Enable building new
display engine with KCOV enabled").
>>>
>>> Ahh. So that was presumably why it was disabled before - because it
>>> presumably does disgusting things that make KCOV generate even bigger
>>> stack frames than it already has.
>>>
>>> Those functions do seem to have fairly big stack footprints already (I
>>> didn't try to look into why, I assume it's partly due to aggressive
>>> inlining, and probably some automatic structures on stack). But gcc
>>> doesn't seem to make it all that much worse with KCOV (and my clang
>>> build doesn't enable KCOV).
>>>
>>> So it's presumably some KCOV-vs-clang thing. Nathan?
>
> Looks like Arnd beat me to it :)
>
>> The dependency was originally added to avoid a link failure in 9d1d02ff3678
>> ("drm/amd/display: Don't build DCN1 when kcov is enabled") after I reported
>> the
>> problem in
>> https://lists.freedesktop.org/archives/dri-devel/2018-August/186131.html>>>
>> The commit from the bisection just turns off KCOV for the entire directory
>> to avoid the link failure, so it's not actually a problem with KCOV vs clang,
>> but I think a problem with clang vs badly written code that was obscured
>> in allmodconfig builds prior to this.
>
> Right, I do think the sanitizers make things worse here too, as those get
> enabled with allmodconfig. I ran some really quick tests with allmodconfig and
> a few instrumentation options flipped on/off:
>
> allmodconfig (CONFIG_KASAN=y, CONFIG_KCSAN=n, CONFIG_KCOV=y, and
> CONFIG_UBSAN=y):
>
> warning: stack frame size (2216) exceeds limit (2048) in
> 'dml30_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
> warning: stack frame size (2184) exceeds limit (2048) in
> 'dml31_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
> warning: stack frame size (2176) exceeds limit (2048) in
> 'dml32_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
>
> allmodconfig + CONFIG_KASAN=n:
>
> warning: stack frame size (2112) exceeds limit (2048) in
> 'dml32_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
>
> allmodconfig + CONFIG_KCOV=n:
>
> warning: stack frame size (2216) exceeds limit (2048) in
> 'dml30_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
> warning: stack frame size (2184) exceeds limit (2048) in
> 'dml31_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
> warning: stack frame size (2176) exceeds limit (2048) in
> 'dml32_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
>
> allmodconfig + CONFIG_UBSAN=n:
>
> warning: stack frame size (2584) exceeds limit (2048) in
> 'dml30_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
> warning: stack frame size (2680) exceeds limit (2048) in
> 'dml31_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
> warning: stack frame size (2352) exceeds limit (2048) in
> 'dml32_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
>
> allmodconfig + CONFIG_KASAN=n + CONFIG_KCSAN=y + CONFIG_UBSAN=n:
>
> warning: stack frame size (2504) exceeds limit (2048) in
> 'dml30_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
> warning: stack frame size (2600) exceeds limit (2048) in
> 'dml31_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
> warning: stack frame size (2264) exceeds limit (2048) in
> 'dml32_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
>
> allmodconfig + CONFIG_KASAN=n + CONFIG_KCSAN=n + CONFIG_UBSAN=n:
>
> warning: stack frame size (2072) exceeds limit (2048) in
> 'dml31_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
>
> There might be other debugging configurations that make this worse too,
> as I don't see those warnings on my distribution configuration.
>
>> The dml30_ModeSupportAndSystemConfigurationFull() function exercises
>> a few paths in the compiler that are otherwise rare. On thing it does is to
>> pass up to 60 arguments to other functions, and it heavily uses float and
>> double variables. Both of these make it rather fragile when it comes to
>> unusual compiler options, so the files keep coming up whenever a new
>> instrumentation feature gets added. There is probably some other flag
>> in allmodconfig that we can disable to improve this again, but I have not
>> checked this time.
>
> I do notice that these files build with a non-configurable
> -Wframe-large-than value:
>
> $ rg frame_warn_flag drivers/gpu/drm/amd/display/dc/dml/Makefile
> 54:frame_warn_flag := -Wframe-larger-than=2048
Tbh, I was looking at the history and I can't find a good reason this
was added. It should be safe to drop this. I would much rather use
the CONFIG_FRAME_WARN value
RE: mainline build failure for x86_64 allmodconfig with clang
... > * NOTE: > * This file is gcc-parsable HW gospel, coming straight from HW engineers. I never trust hardware engineers to write code :-) (Although at the moment they trust me to write VHDL...) David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
Re: mainline build failure for x86_64 allmodconfig with clang
On Thu, Aug 04, 2022 at 02:59:01PM -0700, Linus Torvalds wrote:
> On Thu, Aug 4, 2022 at 1:43 PM Nathan Chancellor wrote:
> >
> > I do note that commit 1b54a0121dba ("drm/amd/display: Reduce stack size
> > in the mode support function") did have a workaround for GCC. It appears
> > clang will still inline mode_support_configuration(). If I mark it as
> > 'noinline', the warning disappears in that file.
>
> That sounds like probably the best option for now. Gcc does not inline
> that function (at least for allmodconfig builds in my testing), so if
> that makes clang match what gcc does, it seems a reasonable thing to
> do.
Sounds good. That solution only takes care of the warning in
display_mode_vba_32.c. I will try and come up with something similar for
the other two files tomorrow, unless the AMD folks beat me to it, since
they will know the driver better than I will ;)
Cheers,
Nathan
Re: mainline build failure for x86_64 allmodconfig with clang
On Thu, Aug 4, 2022 at 1:43 PM Nathan Chancellor wrote:
>
> I do note that commit 1b54a0121dba ("drm/amd/display: Reduce stack size
> in the mode support function") did have a workaround for GCC. It appears
> clang will still inline mode_support_configuration(). If I mark it as
> 'noinline', the warning disappears in that file.
That sounds like probably the best option for now. Gcc does not inline
that function (at least for allmodconfig builds in my testing), so if
that makes clang match what gcc does, it seems a reasonable thing to
do.
Linus
Re: mainline build failure for x86_64 allmodconfig with clang
On Thu, Aug 04, 2022 at 09:24:41PM +0200, Arnd Bergmann wrote:
> On Thu, Aug 4, 2022 at 8:52 PM Linus Torvalds
> wrote:
> >
> > On Thu, Aug 4, 2022 at 11:37 AM Sudip Mukherjee (Codethink)
> > wrote:cov_trace_cmp
> > >
> > > git bisect points to 3876a8b5e241 ("drm/amd/display: Enable building new
> > > display engine with KCOV enabled").
> >
> > Ahh. So that was presumably why it was disabled before - because it
> > presumably does disgusting things that make KCOV generate even bigger
> > stack frames than it already has.
> >
> > Those functions do seem to have fairly big stack footprints already (I
> > didn't try to look into why, I assume it's partly due to aggressive
> > inlining, and probably some automatic structures on stack). But gcc
> > doesn't seem to make it all that much worse with KCOV (and my clang
> > build doesn't enable KCOV).
> >
> > So it's presumably some KCOV-vs-clang thing. Nathan?
Looks like Arnd beat me to it :)
> The dependency was originally added to avoid a link failure in 9d1d02ff3678
> ("drm/amd/display: Don't build DCN1 when kcov is enabled") after I reported
> the
> problem in
> https://lists.freedesktop.org/archives/dri-devel/2018-August/186131.html
>
> The commit from the bisection just turns off KCOV for the entire directory
> to avoid the link failure, so it's not actually a problem with KCOV vs clang,
> but I think a problem with clang vs badly written code that was obscured
> in allmodconfig builds prior to this.
Right, I do think the sanitizers make things worse here too, as those get
enabled with allmodconfig. I ran some really quick tests with allmodconfig and
a few instrumentation options flipped on/off:
allmodconfig (CONFIG_KASAN=y, CONFIG_KCSAN=n, CONFIG_KCOV=y, and
CONFIG_UBSAN=y):
warning: stack frame size (2216) exceeds limit (2048) in
'dml30_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
warning: stack frame size (2184) exceeds limit (2048) in
'dml31_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
warning: stack frame size (2176) exceeds limit (2048) in
'dml32_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
allmodconfig + CONFIG_KASAN=n:
warning: stack frame size (2112) exceeds limit (2048) in
'dml32_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
allmodconfig + CONFIG_KCOV=n:
warning: stack frame size (2216) exceeds limit (2048) in
'dml30_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
warning: stack frame size (2184) exceeds limit (2048) in
'dml31_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
warning: stack frame size (2176) exceeds limit (2048) in
'dml32_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
allmodconfig + CONFIG_UBSAN=n:
warning: stack frame size (2584) exceeds limit (2048) in
'dml30_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
warning: stack frame size (2680) exceeds limit (2048) in
'dml31_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
warning: stack frame size (2352) exceeds limit (2048) in
'dml32_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
allmodconfig + CONFIG_KASAN=n + CONFIG_KCSAN=y + CONFIG_UBSAN=n:
warning: stack frame size (2504) exceeds limit (2048) in
'dml30_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
warning: stack frame size (2600) exceeds limit (2048) in
'dml31_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
warning: stack frame size (2264) exceeds limit (2048) in
'dml32_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
allmodconfig + CONFIG_KASAN=n + CONFIG_KCSAN=n + CONFIG_UBSAN=n:
warning: stack frame size (2072) exceeds limit (2048) in
'dml31_ModeSupportAndSystemConfigurationFull' [-Wframe-larger-than]
There might be other debugging configurations that make this worse too,
as I don't see those warnings on my distribution configuration.
> The dml30_ModeSupportAndSystemConfigurationFull() function exercises
> a few paths in the compiler that are otherwise rare. On thing it does is to
> pass up to 60 arguments to other functions, and it heavily uses float and
> double variables. Both of these make it rather fragile when it comes to
> unusual compiler options, so the files keep coming up whenever a new
> instrumentation feature gets added. There is probably some other flag
> in allmodconfig that we can disable to improve this again, but I have not
> checked this time.
I do notice that these files build with a non-configurable
-Wframe-large-than value:
$ rg frame_warn_flag drivers/gpu/drm/amd/display/dc/dml/Makefile
54:frame_warn_flag := -Wframe-larger-than=2048
70:CFLAGS_$(AMDDALPATH)/dc/dml/dcn30/display_mode_vba_30.o := $(dml_ccflags)
$(frame_warn_flag)
72:CFLAGS_$(AMDDALPATH)/dc/dml/dcn31/display_mode_vba_31.o := $(dml_ccflags)
$(frame_warn_flag)
76:CFLAGS_$(AMDDALPATH)/dc/dml/dcn32/display_mode_vba_32.o := $(dml_ccflags)
$(frame_warn_flag)
I suppose that could just be bumped as a quick workaround? Two of
Re: mainline build failure for x86_64 allmodconfig with clang
On Thu, Aug 4, 2022 at 8:52 PM Linus Torvalds
wrote:
>
> On Thu, Aug 4, 2022 at 11:37 AM Sudip Mukherjee (Codethink)
> wrote:cov_trace_cmp
> >
> > git bisect points to 3876a8b5e241 ("drm/amd/display: Enable building new
> > display engine with KCOV enabled").
>
> Ahh. So that was presumably why it was disabled before - because it
> presumably does disgusting things that make KCOV generate even bigger
> stack frames than it already has.
>
> Those functions do seem to have fairly big stack footprints already (I
> didn't try to look into why, I assume it's partly due to aggressive
> inlining, and probably some automatic structures on stack). But gcc
> doesn't seem to make it all that much worse with KCOV (and my clang
> build doesn't enable KCOV).
>
> So it's presumably some KCOV-vs-clang thing. Nathan?
The dependency was originally added to avoid a link failure in 9d1d02ff3678
("drm/amd/display: Don't build DCN1 when kcov is enabled") after I reported the
problem in
https://lists.freedesktop.org/archives/dri-devel/2018-August/186131.html
The commit from the bisection just turns off KCOV for the entire directory
to avoid the link failure, so it's not actually a problem with KCOV vs clang,
but I think a problem with clang vs badly written code that was obscured
in allmodconfig builds prior to this.
The dml30_ModeSupportAndSystemConfigurationFull() function exercises
a few paths in the compiler that are otherwise rare. On thing it does is to
pass up to 60 arguments to other functions, and it heavily uses float and
double variables. Both of these make it rather fragile when it comes to
unusual compiler options, so the files keep coming up whenever a new
instrumentation feature gets added. There is probably some other flag
in allmodconfig that we can disable to improve this again, but I have not
checked this time.
Arnd
Re: mainline build failure for x86_64 allmodconfig with clang
On Thu, Aug 4, 2022 at 11:37 AM Sudip Mukherjee (Codethink)
wrote:
>
> git bisect points to 3876a8b5e241 ("drm/amd/display: Enable building new
> display engine with KCOV enabled").
Ahh. So that was presumably why it was disabled before - because it
presumably does disgusting things that make KCOV generate even bigger
stack frames than it already has.
Those functions do seem to have fairly big stack footprints already (I
didn't try to look into why, I assume it's partly due to aggressive
inlining, and probably some automatic structures on stack). But gcc
doesn't seem to make it all that much worse with KCOV (and my clang
build doesn't enable KCOV).
So it's presumably some KCOV-vs-clang thing. Nathan?
Linus
mainline build failure for x86_64 allmodconfig with clang
Hi All,
The latest mainline kernel branch fails to build for x86_64 allmodconfig
with clang. The errors are:
drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn30/display_mode_vba_30.c:3596:6:
error: stack frame size (2216) exceeds limit (2048) in
'dml30_ModeSupportAndSystemConfigurationFull' [-Werror,-Wframe-larger-than]
void dml30_ModeSupportAndSystemConfigurationFull(struct display_mode_lib
*mode_lib)
drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn31/display_mode_vba_31.c:3908:6:
error: stack frame size (2184) exceeds limit (2048) in
'dml31_ModeSupportAndSystemConfigurationFull' [-Werror,-Wframe-larger-than]
void dml31_ModeSupportAndSystemConfigurationFull(struct display_mode_lib
*mode_lib)
drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn32/display_mode_vba_32.c:1726:6:
error: stack frame size (2176) exceeds limit (2048) in
'dml32_ModeSupportAndSystemConfigurationFull' [-Werror,-Wframe-larger-than]
void dml32_ModeSupportAndSystemConfigurationFull(struct display_mode_lib
*mode_lib)
git bisect points to 3876a8b5e241 ("drm/amd/display: Enable building new
display engine with KCOV enabled").
My last good build for clang was with e2b542100719 ("Merge tag
'flexible-array-transformations-UAPI-6.0-rc1' of
git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux").
I will be happy to test any patch or provide any extra log if needed.
--
Regards
Sudip
