We are currently having FIFO underruns happening for kms_dsc test case, problem is that, we check if curreny cdclk is >= pixel rate only if there is a single VDSC engine enabled(i.e dsc_split=false) however if we happen to have 2 VDSC engines enabled, we just kinda rely that this would be automatically enough. However pixel rate can be even >= than VDSC clock(cdclk) * 2, so in that case even with 2 VDSC engines enabled, we still need to tweak it up. So lets compare pixel rate with cdclk * slice count(VDSC engine count) and check if it still requires bumping up. Previously we had to bump up CDCLK many times for similar reasons. Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx> --- drivers/gpu/drm/i915/display/intel_cdclk.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c index 4207863b7b2a..5880dcb11588 100644 --- a/drivers/gpu/drm/i915/display/intel_cdclk.c +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c @@ -2607,9 +2607,14 @@ int intel_crtc_compute_min_cdclk(const struct intel_crtc_state *crtc_state) * When we decide to use only one VDSC engine, since * each VDSC operates with 1 ppc throughput, pixel clock * cannot be higher than the VDSC clock (cdclk) + * If there 2 VDSC engines, then pixel clock can't be higher than + * VDSC clock(cdclk) * 2. However even that can still be not enough. + * Slice count reflects amount of VDSC engines, + * so lets use that to determine, if need still need to tweak CDCLK higher. */ - if (crtc_state->dsc.compression_enable && !crtc_state->dsc.dsc_split) - min_cdclk = max(min_cdclk, (int)crtc_state->pixel_rate); + if (crtc_state->dsc.compression_enable) + min_cdclk = max_t(int, min_cdclk * crtc_state->dsc.slice_count, + crtc_state->pixel_rate); /* * HACK. Currently for TGL/DG2 platforms we calculate -- 2.37.3
