Re: [PATCH v1 0/1] tegra_mmc: get tap and trim from dts
24 серпня 2023 р. 16:27:19 GMT+03:00, Thierry Reding написав(-ла): >On Wed, Aug 23, 2023 at 02:30:48PM +0300, Svyatoslav Ryhel wrote: >> >> >> 23 серпня 2023 р. 13:53:26 GMT+03:00, Thierry Reding >> написав(-ла): >> >On Sat, Aug 19, 2023 at 06:35:00PM +0300, Svyatoslav Ryhel wrote: >> >> Default-tap and default-trim values are used for eMMC setup >> >> mostly on T114+ devices. As for now, those values are hardcoded >> >> for T210 and ignored for all other Tegra generations. Fix this >> >> by passing tap and trim values from dts. >> >> >> >> This commit will cause regression on T210 (emmc may not work), >> >> fix is applied in tegra210.dtsi and will be sent next week. >> > >> >Heh... I don't think so. If you already know that this will cause a >> >regression on Tegra210 you need to rework this. Adding regressions >> >accidentally is already bad enough, but doing so knowingly is a big >> >no-no. >> >> DTS change for t210 was sent in "General tegra and board improvements" >> patchset. This is why this pathset contains only 1 (one) patch and a >> warning. It has a dependency. > >For U-Boot this may not matter as much because the control DTB is always >linked into the binary, but for Linux for example we need to make sure >that the kernel always remains backwards compatible with older device >trees. I think that's good to follow in general, so making sure there >are sensible defaults to fall back to if the DTB is missing some >properties is good practice. > >Anyway, the way you posted these there was a future dependency, so if >someone had applied the driver change without the DTB change having been >applied first this would've caused a regression, which is always bad if >it happens at random points because it makes things like bisections very >painful. > >So unless the patch is fixed to fall back to defaults for Tegra210 we >need to carefully coordinate in which order these patches go in. The DT >change needs to go in first, followed by the driver change that relies >on the DTB update. > You are right, it was my miss that I did not include tegra210 fix here. I will add it in v2. Thanks. >Thierry
Re: [PATCH v1 0/1] tegra_mmc: get tap and trim from dts
On Wed, Aug 23, 2023 at 02:30:48PM +0300, Svyatoslav Ryhel wrote: > > > 23 серпня 2023 р. 13:53:26 GMT+03:00, Thierry Reding > написав(-ла): > >On Sat, Aug 19, 2023 at 06:35:00PM +0300, Svyatoslav Ryhel wrote: > >> Default-tap and default-trim values are used for eMMC setup > >> mostly on T114+ devices. As for now, those values are hardcoded > >> for T210 and ignored for all other Tegra generations. Fix this > >> by passing tap and trim values from dts. > >> > >> This commit will cause regression on T210 (emmc may not work), > >> fix is applied in tegra210.dtsi and will be sent next week. > > > >Heh... I don't think so. If you already know that this will cause a > >regression on Tegra210 you need to rework this. Adding regressions > >accidentally is already bad enough, but doing so knowingly is a big > >no-no. > > DTS change for t210 was sent in "General tegra and board improvements" > patchset. This is why this pathset contains only 1 (one) patch and a > warning. It has a dependency. For U-Boot this may not matter as much because the control DTB is always linked into the binary, but for Linux for example we need to make sure that the kernel always remains backwards compatible with older device trees. I think that's good to follow in general, so making sure there are sensible defaults to fall back to if the DTB is missing some properties is good practice. Anyway, the way you posted these there was a future dependency, so if someone had applied the driver change without the DTB change having been applied first this would've caused a regression, which is always bad if it happens at random points because it makes things like bisections very painful. So unless the patch is fixed to fall back to defaults for Tegra210 we need to carefully coordinate in which order these patches go in. The DT change needs to go in first, followed by the driver change that relies on the DTB update. Thierry signature.asc Description: PGP signature
Re: [PATCH v1 0/1] tegra_mmc: get tap and trim from dts
23 серпня 2023 р. 13:53:26 GMT+03:00, Thierry Reding написав(-ла): >On Sat, Aug 19, 2023 at 06:35:00PM +0300, Svyatoslav Ryhel wrote: >> Default-tap and default-trim values are used for eMMC setup >> mostly on T114+ devices. As for now, those values are hardcoded >> for T210 and ignored for all other Tegra generations. Fix this >> by passing tap and trim values from dts. >> >> This commit will cause regression on T210 (emmc may not work), >> fix is applied in tegra210.dtsi and will be sent next week. > >Heh... I don't think so. If you already know that this will cause a >regression on Tegra210 you need to rework this. Adding regressions >accidentally is already bad enough, but doing so knowingly is a big >no-no. DTS change for t210 was sent in "General tegra and board improvements" patchset. This is why this pathset contains only 1 (one) patch and a warning. It has a dependency. >Thierry
Re: [PATCH v1 0/1] tegra_mmc: get tap and trim from dts
On Sat, Aug 19, 2023 at 06:35:00PM +0300, Svyatoslav Ryhel wrote: > Default-tap and default-trim values are used for eMMC setup > mostly on T114+ devices. As for now, those values are hardcoded > for T210 and ignored for all other Tegra generations. Fix this > by passing tap and trim values from dts. > > This commit will cause regression on T210 (emmc may not work), > fix is applied in tegra210.dtsi and will be sent next week. Heh... I don't think so. If you already know that this will cause a regression on Tegra210 you need to rework this. Adding regressions accidentally is already bad enough, but doing so knowingly is a big no-no. Thierry signature.asc Description: PGP signature
[PATCH v1 0/1] tegra_mmc: get tap and trim from dts
Default-tap and default-trim values are used for eMMC setup mostly on T114+ devices. As for now, those values are hardcoded for T210 and ignored for all other Tegra generations. Fix this by passing tap and trim values from dts. This commit will cause regression on T210 (emmc may not work), fix is applied in tegra210.dtsi and will be sent next week. Svyatoslav Ryhel (1): mmc: tegra: get default-tap and default-trim from device tree arch/arm/include/asm/arch-tegra/tegra_mmc.h | 17 drivers/mmc/tegra_mmc.c | 46 ++--- 2 files changed, 30 insertions(+), 33 deletions(-) -- 2.39.2
