This is a note to let you know that I've just added the patch titled
drm/amd/display: Use DTBCLK as refclk instead of DPREFCLK
to the 6.5-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-use-dtbclk-as-refclk-instead-of-dpre.patch
and it can be found in the queue-6.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 2264559251479851e027f5c248244491d8ef33ff
Author: Austin Zheng <austin.zheng@xxxxxxx>
Date: Wed Jul 26 10:40:48 2023 -0400
drm/amd/display: Use DTBCLK as refclk instead of DPREFCLK
[ Upstream commit 4a30cc2bd281fa176a68b5305cd3695d636152ad ]
[Why]
Flash of corruption observed when UCLK switching after transitioning
from DTBCLK to DPREFCLK on subVP(DP) + subVP(HDMI) config
Scenario where DPREFCLK is required instead of DTBCLK is not expected
[How]
Always set the DTBCLK source as DTBCLK0
Reviewed-by: Alvin Lee <alvin.lee2@xxxxxxx>
Acked-by: Tom Chung <chiahsuan.chung@xxxxxxx>
Signed-off-by: Austin Zheng <austin.zheng@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/dcn32/dcn32_dccg.c b/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_dccg.c
index 61ceff6bc0b19..921f58c0c729b 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_dccg.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_dccg.c
@@ -281,7 +281,8 @@ static void dccg32_set_dpstreamclk(
struct dcn_dccg *dccg_dcn = TO_DCN_DCCG(dccg);
/* set the dtbclk_p source */
- dccg32_set_dtbclk_p_src(dccg, src, otg_inst);
+ /* always program refclk as DTBCLK. No use-case expected to require DPREFCLK as refclk */
+ dccg32_set_dtbclk_p_src(dccg, DTBCLK0, otg_inst);
/* enabled to select one of the DTBCLKs for pipe */
switch (dp_hpo_inst) {
