This is a note to let you know that I've just added the patch titled
drm/amd/display: fix FCLK pstate change underflow
to the 6.1-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-fix-fclk-pstate-change-underflow.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 4dc21b911ea2d401734843a2c8eebaa290d5a25d
Author: Vladimir Stempen <vladimir.stempen@xxxxxxx>
Date: Tue Jan 17 14:14:42 2023 -0500
drm/amd/display: fix FCLK pstate change underflow
[ Upstream commit 972243f973eb0821084e5833d5f7f4ed025f42da ]
[Why]
Currently we set FCLK p-state change
watermark calculated based on dummy
p-state latency when UCLK p-state is
not supported
[How]
Calculate FCLK p-state change watermark
based on on FCLK pstate change latency
in case UCLK p-state is not supported
Reviewed-by: Nevenko Stupar <Nevenko.Stupar@xxxxxxx>
Acked-by: Alex Hung <alex.hung@xxxxxxx>
Signed-off-by: Vladimir Stempen <vladimir.stempen@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/dml/dcn32/dcn32_fpu.c b/drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c
index d90216d2fe3a8..04cc96e700981 100644
--- a/drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c
+++ b/drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c
@@ -1963,6 +1963,10 @@ void dcn32_calculate_wm_and_dlg_fpu(struct dc *dc, struct dc_state *context,
*/
context->bw_ctx.bw.dcn.watermarks.a = context->bw_ctx.bw.dcn.watermarks.c;
context->bw_ctx.bw.dcn.watermarks.a.cstate_pstate.pstate_change_ns = 0;
+ /* Calculate FCLK p-state change watermark based on FCLK pstate change latency in case
+ * UCLK p-state is not supported, to avoid underflow in case FCLK pstate is supported
+ */
+ context->bw_ctx.bw.dcn.watermarks.a.cstate_pstate.fclk_pstate_change_ns = get_fclk_watermark(&context->bw_ctx.dml, pipes, pipe_cnt) * 1000;
} else {
/* Set A:
* All clocks min.
