[PATCH V4] drm/dp_mst: Retrieve extended DPCD caps for topology manager

[Lyude Paul]

On Wed, 2020-09-23 at 10:16 +0800, Koba Ko wrote:
> Thanks for the review.
> Sorry for that I thought the review tag should be appended by myself.
> One thing to confirm with you, will you or I push this patch to drm-misc-
> next ?

I already pushed it with the change, so everything is all set

> Thanks a lot.
> 
> On Wed, Sep 23, 2020 at 2:01 AM Lyude Paul <lyude at redhat.com> wrote:
> > One last change I realized we should do is print the name of the AUX
> > adapter
> > in question. I don't mind just adding that myself before I push it though
> > so
> > you don't need to send a respin.
> > 
> > Going to go push this to drm-misc-next, thanks!
> > 
> > On Tue, 2020-09-22 at 14:53 +0800, Koba Ko wrote:
> > > As per DP-1.3, First check DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT.
> > > If DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT is 1,read the DP_DP13_DPCD_REV
> > > to
> > > get the faster capability.
> > > If DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT is 0,read DP_DPCD_REV.
> > > 
> > > Signed-off-by: Koba Ko <koba.ko at canonical.com>
> > > Reviewed-by: Lyude Paul <lyude at redhat.com>
> > > ---
> > >  drivers/gpu/drm/drm_dp_mst_topology.c | 6 +++---
> > >  1 file changed, 3 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c
> > > b/drivers/gpu/drm/drm_dp_mst_topology.c
> > > index e87542533640..63f8809b9aa4 100644
> > > --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> > > +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> > > @@ -3686,9 +3686,9 @@ int drm_dp_mst_topology_mgr_set_mst(struct
> > > drm_dp_mst_topology_mgr *mgr, bool ms
> > >               WARN_ON(mgr->mst_primary);
> > > 
> > >               /* get dpcd info */
> > > -             ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd,
> > > DP_RECEIVER_CAP_SIZE);
> > > -             if (ret != DP_RECEIVER_CAP_SIZE) {
> > > -                     DRM_DEBUG_KMS("failed to read DPCD\n");
> > > +             ret = drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd);
> > > +             if (ret < 0) {
> > > +                     drm_dbg_kms(mgr->dev, "failed to read DPCD, ret
> > > %d\n",
> > > ret);
> > >                       goto out_unlock;
> > >               }
> > > 
> > --
> > Cheers,
> >         Lyude Paul (she/her)
> >         Software Engineer at Red Hat
> > 
-- 
Cheers,
	Lyude Paul (she/her)
	Software Engineer at Red Hat