From 3bb68cec4db82ac9134181557c70c9eeb55ef403 Mon Sep 17 00:00:00 2001 From: Bhawanpreet Lakha Date: Thu, 29 Apr 2021 16:32:47 -0400 Subject: [PATCH] drm/amd/display: Add Overflow check to skip MALL [Why] In some small modes (<200pixels) the stutter period is really big and will cause overflow. In these cases we shouldnt try to enable MALL as it will exceeds range of hysteresis timer (this can be seen in some IGT tests where the plane size is small) [How] Compare the stutter_period with the frame time and if we will overflow there is no point in trying to enable MALL (and see the ASSERT) so we early exist in this case Signed-off-by: Bhawanpreet Lakha Reviewed-by: Jun Lei Acked-by: Stylon Wang Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/dc/dcn30/dcn30_hwseq.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_hwseq.c b/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_hwseq.c index d53f8b3..8368531 100644 --- a/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_hwseq.c +++ b/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_hwseq.c @@ -813,6 +813,15 @@ bool dcn30_apply_idle_power_optimizations(struct dc *dc, bool enable) (100LL + dc->debug.mall_additional_timer_percent) + denom - 1), denom) - 64LL; + /* In some cases the stutter period is really big (tiny modes) in these + * cases MALL cant be enabled, So skip these cases to avoid a ASSERT() + * + * We can check if stutter_period is more than 1/10th the frame time to + * consider if we can actually meet the range of hysteresis timer + */ + if (stutter_period > 100000/refresh_hz) + return false; + /* scale should be increased until it fits into 6 bits */ while (tmr_delay & ~0x3F) { tmr_scale++; -- 2.7.4