From: Mario Limonciello mario.limonciello@amd.com
stable inclusion from stable-v6.6.8 commit c7f6e836e675683e704a40e68eded505bdc30428 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8ST59
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit b96ab339ee50470d13a1faa6ad94d2218a7cd49f upstream.
Mark reports that brightness is not restored after Xorg dpms screen blank.
This behavior was introduced by commit d9e865826c20 ("drm/amd/display: Simplify brightness initialization") which dropped the cached backlight value in display code, but also removed code for when the default value read back was less than 1 nit.
Restore this code so that the backlight brightness is restored to the correct default value in this circumstance.
Reported-by: Mark Herbert mark.herbert42@gmail.com Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3031 Cc: stable@vger.kernel.org Cc: Camille Cho camille.cho@amd.com Cc: Krunoslav Kovac krunoslav.kovac@amd.com Cc: Hamza Mahfooz hamza.mahfooz@amd.com Fixes: d9e865826c20 ("drm/amd/display: Simplify brightness initialization") Acked-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Mario Limonciello mario.limonciello@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- .../amd/display/dc/link/protocols/link_edp_panel_control.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c index fe74d4252a51..13c3d7ff6139 100644 --- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c +++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c @@ -280,8 +280,8 @@ bool set_default_brightness_aux(struct dc_link *link) if (link && link->dpcd_sink_ext_caps.bits.oled == 1) { if (!read_default_bl_aux(link, &default_backlight)) default_backlight = 150000; - // if > 5000, it might be wrong readback - if (default_backlight > 5000000) + // if < 1 nits or > 5000, it might be wrong readback + if (default_backlight < 1000 || default_backlight > 5000000) default_backlight = 150000;
return edp_set_backlight_level_nits(link, true,