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Message-Id: <20221003070715.984212515@linuxfoundation.org> Date: Mon, 3 Oct 2022 09:12:22 +0200 From: Greg Kroah-Hartman <gregkh@...uxfoundation.org> To: linux-kernel@...r.kernel.org Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, stable@...r.kernel.org, Brian Norris <briannorris@...omium.org>, Douglas Anderson <dianders@...omium.org>, Sasha Levin <sashal@...nel.org> Subject: [PATCH 4.19 19/25] Revert "drm: bridge: analogix/dp: add panel prepare/unprepare in suspend/resume time" From: Brian Norris <briannorris@...omium.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@...omium.org> Reviewed-by: Douglas Anderson <dianders@...omium.org> Signed-off-by: Douglas Anderson <dianders@...omium.org> Link: https://patchwork.freedesktop.org/patch/msgid/20220822180729.1.I8ac5abe3a4c1c6fd5c061686c6e883c22f69022c@changeid Signed-off-by: Sasha Levin <sashal@...nel.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 e21c7673cd5b..57781833cae1 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c @@ -1690,12 +1690,6 @@ EXPORT_SYMBOL_GPL(analogix_dp_unbind); 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); @@ -1710,13 +1704,6 @@ 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); -- 2.35.1
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