This is a note to let you know that I've just added the patch titled drm/amd/display: clear optc underflow before turn off odm clock to the 5.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-amd-display-clear-optc-underflow-before-turn-off.patch and it can be found in the queue-5.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 28f1aa63df3ab4f54dddb54b7c8d961ad6febede Author: Fudong Wang <Fudong.Wang@xxxxxxx> Date: Wed Jul 27 12:01:29 2022 +0800 drm/amd/display: clear optc underflow before turn off odm clock [ Upstream commit b2a93490201300a749ad261b5c5d05cb50179c44 ] [Why] After ODM clock off, optc underflow bit will be kept there always and clear not work. We need to clear that before clock off. [How] Clear that if have when clock off. Reviewed-by: Alvin Lee <alvin.lee2@xxxxxxx> Acked-by: Tom Chung <chiahsuan.chung@xxxxxxx> Signed-off-by: Fudong Wang <Fudong.Wang@xxxxxxx> Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c index b1671b00ce405..2349977b0abb2 100644 --- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c +++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c @@ -464,6 +464,11 @@ void optc1_enable_optc_clock(struct timing_generator *optc, bool enable) OTG_CLOCK_ON, 1, 1, 1000); } else { + + //last chance to clear underflow, otherwise, it will always there due to clock is off. + if (optc->funcs->is_optc_underflow_occurred(optc) == true) + optc->funcs->clear_optc_underflow(optc); + REG_UPDATE_2(OTG_CLOCK_CONTROL, OTG_CLOCK_GATE_DIS, 0, OTG_CLOCK_EN, 0);