Re: [PATCH 0/4] drm: Revert and fix enable/disable sequence

[Marek Szyprowski <m.szyprowski@samsung.com>]

On 05.12.2025 10:51, Tomi Valkeinen wrote:
> Changing the enable/disable sequence in commit c9b1150a68d9
> ("drm/atomic-helper: Re-order bridge chain pre-enable and post-disable")
> has caused regressions on multiple platforms: R-Car, MCDE, Rockchip.
>
> This is an alternate series to Linus' series:
>
> https://lore.kernel.org/all/20251202-mcde-drm-regression-thirdfix-v6-0-f1bffd4ec0fa%40kernel.org/
>
> This series first reverts the original commit and reverts a fix for
> mediatek which is no longer needed. It then exposes helper functions
> from DRM core, and finally implements the new sequence only in the tidss
> driver.
>
> There is one more fix in upstream for the original commit, commit
> 5d91394f2361 ("drm/exynos: fimd: Guard display clock control with
> runtime PM calls"), but I have not reverted that one as it looks like a
> valid patch in its own.

Right, that patch is a fix on its own, the changes in the atomic 
sequence just revealed the issue.

> I added Cc stable v6.17+ to all patches, but I didn't add Fixes tags, as
> I wasn't sure what should they point to. But I could perhaps add Fixes:
> <original commit> to all of these.
>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> ---
> Linus Walleij (1):
>        drm/atomic-helper: Export and namespace some functions
>
> Tomi Valkeinen (3):
>        Revert "drm/atomic-helper: Re-order bridge chain pre-enable and post-disable"
>        Revert "drm/mediatek: dsi: Fix DSI host and panel bridge pre-enable order"
>        drm/tidss: Fix enable/disable order
>
>   drivers/gpu/drm/drm_atomic_helper.c | 122 ++++++++++++++----
>   drivers/gpu/drm/mediatek/mtk_dsi.c  |   6 -
>   drivers/gpu/drm/tidss/tidss_kms.c   |  30 ++++-
>   include/drm/drm_atomic_helper.h     |  22 ++++
>   include/drm/drm_bridge.h            | 249 ++++++++++--------------------------
>   5 files changed, 214 insertions(+), 215 deletions(-)
> ---
> base-commit: 88e721ab978a86426aa08da520de77430fa7bb84
> change-id: 20251205-drm-seq-fix-b4ed1f56604b

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland