On Mon, May 15, 2023 at 05:44:51PM +0300, Ville Syrjälä wrote: > On Fri, May 12, 2023 at 11:54:09AM +0530, Ankit Nautiyal wrote: > > As per Bsepc:49259, Bigjoiner BW check puts restriction on the > > compressed bpp for a given CDCLK, pixelclock in cases where > > Bigjoiner + DSC are used. > > > > Currently compressed bpp is computed first, and it is ensured that > > the bpp will work at least with the max CDCLK freq. > > > > Since the CDCLK is computed later, lets account for Bigjoiner BW > > check while calculating Min CDCLK. > > > > Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx> > > --- > > drivers/gpu/drm/i915/display/intel_cdclk.c | 49 ++++++++++++++++++---- > > 1 file changed, 42 insertions(+), 7 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c > > index 6bed75f1541a..3532640c5027 100644 > > --- a/drivers/gpu/drm/i915/display/intel_cdclk.c > > +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c > > @@ -2520,6 +2520,46 @@ static int intel_planes_min_cdclk(const struct intel_crtc_state *crtc_state) > > return min_cdclk; > > } > > > > +static int intel_vdsc_min_cdclk(const struct intel_crtc_state *crtc_state) > > +{ > > + struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc); > > + struct drm_i915_private *i915 = to_i915(crtc->base.dev); > > + int min_cdclk = 0; > > + > > + /* > > + * 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 (!crtc_state->dsc.dsc_split) > > + min_cdclk = max(min_cdclk, (int)crtc_state->pixel_rate); > > + > > + if (crtc_state->bigjoiner_pipes) { > > + /* > > + * According to Bigjoiner bw check: > > + * compressed_bpp <= PPC * CDCLK * Big joiner Interface bits / Pixel clock > > + * > > + * We have already computed compressed_bpp, so now compute the min CDCLK that > > + * is required to support this compressed_bpp. > > + * > > + * => CDCLK >= compressed_bpp * Pixel clock / (PPC * Bigjoiner Interface bits) > > + * > > + * Since Num of pipes joined = 2, and PPC = 2 with bigjoiner > > + * => CDCLK >= compressed_bpp * pixel_rate / Bigjoiner Interface bits > > + * > > + * #TODO Bspec mentions to account for FEC overhead while using pixel clock. > > + * Check if we need to use FEC overhead in the above calculations. > > + */ > > + int bigjoiner_interface_bits = DISPLAY_VER(i915) > 13 ? 36 : 24; > > + int min_cdclk_bj = crtc_state->dsc.compressed_bpp * crtc_state->pixel_rate / > > + bigjoiner_interface_bits; > > pixel_rate is the downscale adjusted thing, so it doesn't seem > like the correct thing to use here. > > Hmm. Assuming that the single VDSC engine really throttles the entire > pipe to 1 PPC then we should probably account for the 1 vs. 2 PPC > difference in *_plane_min_cdclk() and intel_pixel_rate_to_cdclk() > directly. Currently all of those assume 2 PPC. Main thing is to properly align that one you propose above with that check, where we decide how many VDSC engines to use: /* * VDSC engine operates at 1 Pixel per clock, so if peak pixel rate * is greater than the maximum Cdclock and if slice count is even * then we need to use 2 VDSC instances. */ if (adjusted_mode->crtc_clock > dev_priv->max_cdclk_freq) { if (pipe_config->dsc.slice_count > 1) { pipe_config->dsc.dsc_split = true; } else { drm_dbg_kms(&dev_priv->drm, "Cannot split stream to use 2 VDSC instances\n"); return -EINVAL; } } Otherwise I agree that we should do that check preferrably in *_plane_min_cdclk and use plane data rate which is adjusted after scaling is applied(I think we even have correspondent function there) It is strange that scaling wasn't mentioned in BSpec formula. I would also say that we should account for number of slices(i.e VDSC engines) now only in Bigjoiner case, but always, as I understand that number can be different not only for Bigjoiner cases. Stan > > > + > > + min_cdclk = max(min_cdclk, min_cdclk_bj); > > + } > > + > > + return min_cdclk; > > +} > > + > > int intel_crtc_compute_min_cdclk(const struct intel_crtc_state *crtc_state) > > { > > struct drm_i915_private *dev_priv = > > @@ -2591,13 +2631,8 @@ int intel_crtc_compute_min_cdclk(const struct intel_crtc_state *crtc_state) > > /* Account for additional needs from the planes */ > > min_cdclk = max(intel_planes_min_cdclk(crtc_state), min_cdclk); > > > > - /* > > - * 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 (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(min_cdclk, intel_vdsc_min_cdclk(crtc_state)); > > > > /* > > * HACK. Currently for TGL/DG2 platforms we calculate > > -- > > 2.25.1 > > -- > Ville Syrjälä > Intel