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.