On Tue, Jan 03, 2023 at 11:32:28AM -0500, Rodrigo Vivi wrote:
>
> on the subject: This is not a hw workaround. Please remove the workaround from
> the subject and the wrong comment.
>
> "The HSD given is a 'feature' rather than 'bugeco' so no workaround details are
> present here."
>
>
> On Mon, Jan 02, 2023 at 01:39:37PM +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.
> >
> > Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/display/intel_dp.c | 11 +++++++++++
> > 1 file changed, 11 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> > index bf80f296a8fdb..13baf3cb5f934 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > @@ -1582,6 +1582,17 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> > drm_dbg_kms(&dev_priv->drm, "DSC: compressed bpp %d slice count %d\n",
> > pipe_config->dsc.compressed_bpp,
> > pipe_config->dsc.slice_count);
> > +
> > + /* wa1406899791 */
>
> even if it was a bugeco, the notation doesn't follow the standard.
>
> But anyway, as I pointed out, this is not a workaround so
> you probably just want a
>
> HSDES: 1406899791
> BSPEC: 49259
>
> in your commit msg.
Ok, will add this thanks.
>
> Also maybe a "Fixes:" tag pointing to the commit that added the sequence
> but didn't added this part of the sequence?
>
> > + if (intel_dp_is_uhbr(pipe_config)) {
> > + int output_bpp = pipe_config->dsc.compressed_bpp;
> > +
> > + if (output_bpp * adjusted_mode->crtc_clock >=
> > + pipe_config->port_clock * 72) {
> > + drm_dbg_kms(&dev_priv->drm, "DP2 UHBR check failed\n");
>
> some probably dummy question:
> do we need to add a check for the DP 2.0 above as well?
> or it is unecessary/redundant?
I think this check is more related to hardware limitation, rather than
DP 2.0 standard. I mean if it was even not DP 2.0, but still UHBR I really doubt
that this limitation wouldn't be essential still.
Stan
>
> > + return -EINVAL;
> > + }
> > + }
> > }
> > /*
> > * VDSC engine operates at 1 Pixel per clock, so if peak pixel rate
> > --
> > 2.37.3
> >
