On Mon, Jan 16, 2023 at 01:19:37PM +0200, Stanislav Lisovskiy wrote: > According to spec, we should check if output_bpp * pixel_rate is less > than DDI clock * 72, if UHBR is used. > > HSDES: 1406899791 > BSPEC: 49259 > > v2: - Removed wrong comment(Rodrigo Vivi) > - Added HSDES to the commit msg(Rodrigo Vivi) > - Moved UHBR check to the MST specific code > > v3: - Changed commit subject(Rodrigo Vivi) > - Fixed the error message if check fails(Rodrigo Vivi) > > v4: - Move UHBR check to new helper function > - Now both for non-DSC/DSC we use that new check as > one of the constraints, when figuring out output bpp > to be used(Ville Syrjälä) > > Signed-off-by: Stanislav Lisovskiy <[email protected]> > --- > drivers/gpu/drm/i915/display/intel_dp_mst.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c > b/drivers/gpu/drm/i915/display/intel_dp_mst.c > index e3e7c305fece..b95051fed23d 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c > +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c > @@ -47,8 +47,19 @@ > > static int intel_dp_mst_check_constraints(struct drm_i915_private *i915, int > bpp, > const struct drm_display_mode > *adjusted_mode, > - struct intel_crtc_state *crtc_state) > + struct intel_crtc_state *pipe_config) > { > + if (intel_dp_is_uhbr(pipe_config)) { > + int output_bpp = bpp; > + > + if (output_bpp * adjusted_mode->crtc_clock >= > + pipe_config->port_clock * 72) {
This seems to be some DSC specific constraint, but this code appears to apply it also to uncompresed output. Also DDICLK != port_clock, so this looks to be off by quite a lot. > + drm_dbg_kms(&i915->drm, "UHBR check failed(required bw > %d available %d)\n", > + output_bpp * adjusted_mode->crtc_clock, > pipe_config->port_clock * 72); > + return -EINVAL; > + } > + } > + > return 0; > } > > -- > 2.37.3 -- Ville Syrjälä Intel
