Hi, On 02/12/2025 08:34, Laurent Pinchart wrote: > Hi Linus, > > On Sun, Nov 30, 2025 at 01:11:16PM +0100, Linus Walleij wrote: >> This fixes two regressions experienced in the MCDE and >> R-Car DU DRM drivers after >> commit c9b1150a68d9362a0827609fc0dc1664c0d8bfe1 >> "drm/atomic-helper: Re-order bridge chain pre-enable and post-disable" >> caused a series of regressions in all panels that send >> DSI commands in their .prepare() and .unprepare() >> callbacks. >> >> This series make it possible to selectively bring back the >> old behaviour with explicit semantics and implements >> the old behaviour as modified commit tails in MCDE and >> R-Car DU. > > We now have a third platform broken by > c9b1150a68d9362a0827609fc0dc1664c0d8bfe1, see [1]. I think this calls > for a revert, to give us the time to implement a correct solution. Perhaps... It's been very slow or not possible to get feedback regarding (some) of the broken platforms, so I don't think we have a safe way of changing the enable/disable sequence. I think the "correct" solution then is to make this new enable/disable sequence either opt-in, offered by the framework, or just implement it as a custom sequence in the specific drm driver.
Reverting c9b1150a68d9362a0827609fc0dc1664c0d8bfe1 will break DSI and OLDI outputs on TI platforms, so we need to implement a fix for those platforms before the revert, and there has been one or two fixes merged for other platforms for this, which most likely also need to get reverted. Tomi > [1] > https://lore.kernel.org/r/caamcf8di8sc_xvzanzq9suiuf-ayvg2yjhx2dwmvvcnff3p...@mail.gmail.com > >> Signed-off-by: Linus Walleij <[email protected]> >> --- >> Changes in v5: >> - Prefix all exported atomic commit helpers with drm_atomic_helper_commit_* >> - Add kerneldoc to all new exported atmomic commit helpers. >> - Add comments into the MCDE and Rcar DU quirks explaining what is >> altered as compared to the standard helper functions. >> - Link to v4: >> https://lore.kernel.org/r/20251121-mcde-drm-regression-thirdfix-v4-0-d89bf8c17...@linaro.org >> >> Changes in v4: >> - Fix a copypaste-bug in the Renesas Rcar-DU driver. >> - Actually compile this using the shmobile defconfig and make >> sure it works. >> - Collect Geert's Tested-by. >> - Link to v3: >> https://lore.kernel.org/r/20251120-mcde-drm-regression-thirdfix-v3-0-24b1e9886...@linaro.org >> >> Changes in v3: >> - Switch to a new approach: export helper functions and create the >> special helper directly in the driver instead. >> - Drop Marek's patch and write a new RFT patch with the same >> semantic content as the MCDE patch. >> - Link to v2: >> https://lore.kernel.org/r/[email protected] >> >> Changes in v2: >> - Queue Marek's patch first in the series for coherency. >> - Add a patch to also preserve the late CRTC disablement >> semantic. >> - Rename helper function to reflect the new semantic. >> - Update the MCDE patch to use the new callbacks. >> - Link to v1: >> https://lore.kernel.org/r/[email protected] >> >> --- >> Linus Walleij (3): >> drm/atomic-helper: Export and namespace some functions >> drm/mcde: Create custom commit tail >> drm/rcar-du: Modify custom commit tail >> >> drivers/gpu/drm/drm_atomic_helper.c | 122 >> +++++++++++++++++++++----- >> drivers/gpu/drm/mcde/mcde_drv.c | 45 +++++++++- >> drivers/gpu/drm/renesas/rcar-du/rcar_du_kms.c | 33 ++++++- >> include/drm/drm_atomic_helper.h | 22 +++++ >> 4 files changed, 195 insertions(+), 27 deletions(-) >> --- >> base-commit: 6548d364a3e850326831799d7e3ea2d7bb97ba08 >> change-id: 20251120-mcde-drm-regression-thirdfix-1b0abfb52209 >
