From: Brian Norris briannorris@chromium.org
[ Upstream commit cc62d98bd56d45de4531844ca23913a15136c05b ]
This reverts commit 211f276ed3d96e964d2d1106a198c7f4a4b3f4c0.
For quite some time, core DRM helpers already ensure that any relevant connectors/CRTCs/etc. are disabled, as well as their associated components (e.g., bridges) when suspending the system. Thus, analogix_dp_bridge_{enable,disable}() already get called, which in turn call drm_panel_{prepare,unprepare}(). This makes these drm_panel_*() calls redundant.
Besides redundancy, there are a few problems with this handling:
(1) drm_panel_{prepare,unprepare}() are *not* reference-counted APIs and are not in general designed to be handled by multiple callers -- although some panel drivers have a coarse 'prepared' flag that mitigates some damage, at least. So at a minimum this is redundant and confusing, but in some cases, this could be actively harmful.
(2) The error-handling is a bit non-standard. We ignored errors in suspend(), but handled errors in resume(). And recently, people noticed that the clk handling is unbalanced in error paths, and getting *that* right is not actually trivial, given the current way errors are mostly ignored.
(3) In the particular way analogix_dp_{suspend,resume}() get used (e.g., in rockchip_dp_*(), as a late/early callback), we don't necessarily have a proper PM relationship between the DP/bridge device and the panel device. So while the DP bridge gets resumed, the panel's parent device (e.g., platform_device) may still be suspended, and so any prepare() calls may fail.
So remove the superfluous, possibly-harmful suspend()/resume() handling of panel state.
Fixes: 211f276ed3d9 ("drm: bridge: analogix/dp: add panel prepare/unprepare in suspend/resume time") Link: https://lore.kernel.org/all/Yv2CPBD3Picg%2FgVe@google.com/ Signed-off-by: Brian Norris briannorris@chromium.org Reviewed-by: Douglas Anderson dianders@chromium.org Signed-off-by: Douglas Anderson dianders@chromium.org Link: https://patchwork.freedesktop.org/patch/msgid/20220822180729.1.I8ac5abe3a4c1... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 13 ------------- 1 file changed, 13 deletions(-)
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c index c6a51d1c7ec9..df606a567566 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c @@ -1823,12 +1823,6 @@ EXPORT_SYMBOL_GPL(analogix_dp_remove); int analogix_dp_suspend(struct analogix_dp_device *dp) { clk_disable_unprepare(dp->clock); - - if (dp->plat_data->panel) { - if (drm_panel_unprepare(dp->plat_data->panel)) - DRM_ERROR("failed to turnoff the panel\n"); - } - return 0; } EXPORT_SYMBOL_GPL(analogix_dp_suspend); @@ -1843,13 +1837,6 @@ int analogix_dp_resume(struct analogix_dp_device *dp) return ret; }
- if (dp->plat_data->panel) { - if (drm_panel_prepare(dp->plat_data->panel)) { - DRM_ERROR("failed to setup the panel\n"); - return -EBUSY; - } - } - return 0; } EXPORT_SYMBOL_GPL(analogix_dp_resume);