On 14/02/2022 17:06, Alyssa Rosenzweig wrote: > On Mon, Feb 14, 2022 at 04:23:18PM +0000, Steven Price wrote: >> On 11/02/2022 20:27, [email protected] wrote: >>> From: Alyssa Rosenzweig <[email protected]> >>> >>> Some Valhall GPUs require resets when encountering bus faults due to >>> occlusion query writes. Add the issue bit for this and handle it. >>> >>> Signed-off-by: Alyssa Rosenzweig <[email protected]> >> >> Reviewed-by: Steven Price <[email protected]> >> (although one nit below) >> >> Just in case any one is wondering - these bus faults occur when >> switching the GPU's MMU to unmapped - it's not a normal "bus fault" from >> the external bus. This is triggered by an attempt to read unmapped >> memory which is completed by the driver by switching the entire MMU to >> unmapped. > > Ouch, that's subtle. > >>> diff --git a/drivers/gpu/drm/panfrost/panfrost_issues.h >>> b/drivers/gpu/drm/panfrost/panfrost_issues.h >>> index a66692663833..058f6a4c8435 100644 >>> --- a/drivers/gpu/drm/panfrost/panfrost_issues.h >>> +++ b/drivers/gpu/drm/panfrost/panfrost_issues.h >>> @@ -128,6 +128,10 @@ enum panfrost_hw_issue { >>> /* Must set SC_VAR_ALGORITHM */ >>> HW_ISSUE_TTRX_2968_TTRX_3162, >>> >>> + /* Bus fault from occlusion query write may cause future fragment jobs >>> + * to hang */ >> >> NIT: Kernel comment style has the "/*" and "*/" on lines by themselves >> for multi-line comments. checkpatch will complain! > > Yes, I am aware (and checkpatch did complain). The existing multi-line > comments in that file do not have the extra lines. Consistency within > the file seemed like the lesser evil. If you think it's better to > appease checkpatch, I can reformat for v2. > > (I can also throw in a patch fixing the rest of that file's multiline > comments but that seems a bit extra.)
Nah! I've never been very keen on that style rule myself, but I usually try to keep checkpatch happy when working on the kernel. Lets just follow the rest of the file for now. Thanks, Steve
