[PATCH] drm/radeon/dp: check for errors in dpcd reads

[Deucher, Alexander]

> -----Original Message-----
> From: Sergei Antonov [mailto:saproj at gmail.com]
> Sent: Monday, May 05, 2014 4:55 PM
> To: Christian König
> Cc: Alex Deucher; dri-devel at lists.freedesktop.org; Deucher, Alexander
> Subject: Re: [PATCH] drm/radeon/dp: check for errors in dpcd reads
> 
> 
> 
> > Am 30.04.2014 um 15:58 schrieb Christian König
> <deathsimple at vodafone.de>:
> >
> > Am 30.04.2014 15:27, schrieb Alex Deucher:
> >> Check to make sure the transaction succeeded before
> >> using the register value.  Fixes occasional link training
> >> problems.
> >>
> >> Noticed-by: Sergei Antonov <saproj at gmail.com>
> >> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> >
> > Applied to my 3.15 queue.
> >
> > Christian.
> 
> Why is not this patch still in Linus' tree? I looked forward to seeing it in 3.15-
> rc4 but it is not there.

It hasn't been pulled into Dave's tree yet.  It should show up in his next pull request to Linus this week.

Alex

> 
> >
> >> ---
> >>  drivers/gpu/drm/radeon/atombios_dp.c | 44 ++++++++++++++++++++-
> ---------------
> >>  1 file changed, 25 insertions(+), 19 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/radeon/atombios_dp.c
> b/drivers/gpu/drm/radeon/atombios_dp.c
> >> index bc0119f..54e4f52 100644
> >> --- a/drivers/gpu/drm/radeon/atombios_dp.c
> >> +++ b/drivers/gpu/drm/radeon/atombios_dp.c
> >> @@ -366,11 +366,11 @@ static void radeon_dp_probe_oui(struct
> radeon_connector *radeon_connector)
> >>      if (!(dig_connector->dpcd[DP_DOWN_STREAM_PORT_COUNT] &
> DP_OUI_SUPPORT))
> >>          return;
> >>  -    if (drm_dp_dpcd_read(&radeon_connector->ddc_bus->aux,
> DP_SINK_OUI, buf, 3))
> >> +    if (drm_dp_dpcd_read(&radeon_connector->ddc_bus->aux,
> DP_SINK_OUI, buf, 3) == 3)
> >>          DRM_DEBUG_KMS("Sink OUI: %02hx%02hx%02hx\n",
> >>                    buf[0], buf[1], buf[2]);
> >>  -    if (drm_dp_dpcd_read(&radeon_connector->ddc_bus->aux,
> DP_BRANCH_OUI, buf, 3))
> >> +    if (drm_dp_dpcd_read(&radeon_connector->ddc_bus->aux,
> DP_BRANCH_OUI, buf, 3) == 3)
> >>          DRM_DEBUG_KMS("Branch OUI: %02hx%02hx%02hx\n",
> >>                    buf[0], buf[1], buf[2]);
> >>  }
> >> @@ -419,21 +419,23 @@ int radeon_dp_get_panel_mode(struct
> drm_encoder *encoder,
> >>        if (dp_bridge != ENCODER_OBJECT_ID_NONE) {
> >>          /* DP bridge chips */
> >> -        drm_dp_dpcd_readb(&radeon_connector->ddc_bus->aux,
> >> -                  DP_EDP_CONFIGURATION_CAP, &tmp);
> >> -        if (tmp & 1)
> >> -            panel_mode = DP_PANEL_MODE_INTERNAL_DP2_MODE;
> >> -        else if ((dp_bridge == ENCODER_OBJECT_ID_NUTMEG) ||
> >> -             (dp_bridge == ENCODER_OBJECT_ID_TRAVIS))
> >> -            panel_mode = DP_PANEL_MODE_INTERNAL_DP1_MODE;
> >> -        else
> >> -            panel_mode = DP_PANEL_MODE_EXTERNAL_DP_MODE;
> >> +        if (drm_dp_dpcd_readb(&radeon_connector->ddc_bus->aux,
> >> +                      DP_EDP_CONFIGURATION_CAP, &tmp) == 1) {
> >> +            if (tmp & 1)
> >> +                panel_mode = DP_PANEL_MODE_INTERNAL_DP2_MODE;
> >> +            else if ((dp_bridge == ENCODER_OBJECT_ID_NUTMEG) ||
> >> +                 (dp_bridge == ENCODER_OBJECT_ID_TRAVIS))
> >> +                panel_mode = DP_PANEL_MODE_INTERNAL_DP1_MODE;
> >> +            else
> >> +                panel_mode = DP_PANEL_MODE_EXTERNAL_DP_MODE;
> >> +        }
> >>      } else if (connector->connector_type ==
> DRM_MODE_CONNECTOR_eDP) {
> >>          /* eDP */
> >> -        drm_dp_dpcd_readb(&radeon_connector->ddc_bus->aux,
> >> -                  DP_EDP_CONFIGURATION_CAP, &tmp);
> >> -        if (tmp & 1)
> >> -            panel_mode = DP_PANEL_MODE_INTERNAL_DP2_MODE;
> >> +        if (drm_dp_dpcd_readb(&radeon_connector->ddc_bus->aux,
> >> +                      DP_EDP_CONFIGURATION_CAP, &tmp) == 1) {
> >> +            if (tmp & 1)
> >> +                panel_mode = DP_PANEL_MODE_INTERNAL_DP2_MODE;
> >> +        }
> >>      }
> >>        return panel_mode;
> >> @@ -809,11 +811,15 @@ void radeon_dp_link_train(struct drm_encoder
> *encoder,
> >>      else
> >>          dp_info.enc_id |= ATOM_DP_CONFIG_LINK_A;
> >>  -    drm_dp_dpcd_readb(&radeon_connector->ddc_bus->aux,
> DP_MAX_LANE_COUNT, &tmp);
> >> -    if (ASIC_IS_DCE5(rdev) && (tmp & DP_TPS3_SUPPORTED))
> >> -        dp_info.tp3_supported = true;
> >> -    else
> >> +    if (drm_dp_dpcd_readb(&radeon_connector->ddc_bus->aux,
> DP_MAX_LANE_COUNT, &tmp)
> >> +        == 1) {
> >> +        if (ASIC_IS_DCE5(rdev) && (tmp & DP_TPS3_SUPPORTED))
> >> +            dp_info.tp3_supported = true;
> >> +        else
> >> +            dp_info.tp3_supported = false;
> >> +    } else {
> >>          dp_info.tp3_supported = false;
> >> +    }
> >>        memcpy(dp_info.dpcd, dig_connector->dpcd,
> DP_RECEIVER_CAP_SIZE);
> >>      dp_info.rdev = rdev;
> >