On Fri, Apr 17, 2020 at 02:51:39PM -0400, Lyude Paul wrote:
> Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx>
>
Thanks. Series pushed to dinq.
> On Fri, 2020-04-17 at 18:27 +0300, Ville Syrjala wrote:
> > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> >
> > Make intel_dp_check_mst_status() somewhat legible by humans.
> >
> > Note that the return value of drm_dp_mst_hpd_irq() is always
> > either 0 or -ENOMEM, and we never did anything with the latter
> > so we can just ignore the whole thing.
> >
> > We can also get rid of the direct drm_dp_mst_topology_mgr_set_mst(false)
> > call since returning -EINVAL causes the caller to do the very same call
> > for us.
> >
> > Cc: Lyude Paul <lyude@xxxxxxxxxx>
> > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/display/intel_dp.c | 88 ++++++++++++-------------
> > 1 file changed, 41 insertions(+), 47 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> > b/drivers/gpu/drm/i915/display/intel_dp.c
> > index 48397b2c08cf..4d4898db38e9 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > @@ -5628,61 +5628,55 @@ static int
> > intel_dp_check_mst_status(struct intel_dp *intel_dp)
> > {
> > struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> > - bool bret;
> >
> > - if (intel_dp->is_mst) {
> > - u8 esi[DP_DPRX_ESI_LEN] = { 0 };
> > - int ret = 0;
> > + if (!intel_dp->is_mst)
> > + return -EINVAL;
> > +
> > + WARN_ON_ONCE(intel_dp->active_mst_links < 0);
> > +
> > + for (;;) {
> > + u8 esi[DP_DPRX_ESI_LEN] = {};
> > + bool bret, handled;
> > int retry;
> > - bool handled;
> >
> > - WARN_ON_ONCE(intel_dp->active_mst_links < 0);
> > bret = intel_dp_get_sink_irq_esi(intel_dp, esi);
> > -go_again:
> > - if (bret == true) {
> > -
> > - /* check link status - esi[10] = 0x200c */
> > - if (intel_dp->active_mst_links > 0 &&
> > - !drm_dp_channel_eq_ok(&esi[10], intel_dp-
> > >lane_count)) {
> > - drm_dbg_kms(&i915->drm,
> > - "channel EQ not ok,
> > retraining\n");
> > - intel_dp_start_link_train(intel_dp);
> > - intel_dp_stop_link_train(intel_dp);
> > - }
> > -
> > - drm_dbg_kms(&i915->drm, "got esi %3ph\n", esi);
> > - ret = drm_dp_mst_hpd_irq(&intel_dp->mst_mgr, esi,
> > &handled);
> > -
> > - if (handled) {
> > - for (retry = 0; retry < 3; retry++) {
> > - int wret;
> > - wret = drm_dp_dpcd_write(&intel_dp-
> > >aux,
> > - DP_SINK_COUNT
> > _ESI+1,
> > - &esi[1], 3);
> > - if (wret == 3) {
> > - break;
> > - }
> > - }
> > -
> > - bret = intel_dp_get_sink_irq_esi(intel_dp,
> > esi);
> > - if (bret == true) {
> > - drm_dbg_kms(&i915->drm,
> > - "got esi2 %3ph\n", esi);
> > - goto go_again;
> > - }
> > - } else
> > - ret = 0;
> > -
> > - return ret;
> > - } else {
> > + if (!bret) {
> > drm_dbg_kms(&i915->drm,
> > "failed to get ESI - device may have
> > failed\n");
> > - intel_dp->is_mst = false;
> > - drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst_mgr,
> > - intel_dp->is_mst);
> > + return -EINVAL;
> > + }
> > +
> > + /* check link status - esi[10] = 0x200c */
> > + /*
> > + * FIXME kill this and use the SST retraining approach
> > + * for MST as well.
> > + */
> > + if (intel_dp->active_mst_links > 0 &&
> > + !drm_dp_channel_eq_ok(&esi[10], intel_dp->lane_count)) {
> > + drm_dbg_kms(&i915->drm,
> > + "channel EQ not ok, retraining\n");
> > + intel_dp_start_link_train(intel_dp);
> > + intel_dp_stop_link_train(intel_dp);
> > + }
> > +
> > + drm_dbg_kms(&i915->drm, "got esi %3ph\n", esi);
> > +
> > + drm_dp_mst_hpd_irq(&intel_dp->mst_mgr, esi, &handled);
> > + if (!handled)
> > + break;
> > +
> > + for (retry = 0; retry < 3; retry++) {
> > + int wret;
> > +
> > + wret = drm_dp_dpcd_write(&intel_dp->aux,
> > + DP_SINK_COUNT_ESI+1,
> > + &esi[1], 3);
> > + if (wret == 3)
> > + break;
> > }
> > }
> > - return -EINVAL;
> > +
> > + return 0;
> > }
> >
> > static bool
> > --
> > 2.24.1
> >
> --
> Cheers,
> Lyude Paul (she/her)
> Associate Software Engineer at Red Hat
--
Ville Syrjälä
Intel
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