[Intel-gfx] [PATCH] drm/i915/hdmi: Fix weak connector detection

[Ezequiel Garcia]

El abr. 1, 2016 11:47 AM, "Ville Syrjälä" <ville.syrjala at linux.intel.com>
escribió:
>
> On Thu, Mar 31, 2016 at 05:55:03PM -0300, Ezequiel Garcia wrote:
> > Currently, our implementation of drm_connector_funcs.detect is
> > based on getting a valid EDID.
> >
> > This requirement makes the driver fail to detect connected
> > connectors in case of EDID corruption, which prevents from falling
> > back to modes provided by builtin or user-provided EDIDs.
>
> So why are you getting corrupted EDIDs?
>

Does it matter?

> >
> > Let's fix this by improving the detection, with a DDC probe,
> > if the current EDID-based detection failed.
> >
> > Note that a better way of dealing with this could calling
> > drm_probe_ddc in drm_connector_funcs.detect, and do the
> > EDID full reading and parsing in drm_connector_helper_funcs.get_modes,
> > when it's actually needed.
> >
> > However, this would be more invasive and thus more error-prone.
> > The current commit is an attempt to get some uninvasive fix,
> > and allow for easier backporting.
> >
> > Signed-off-by: Ezequiel Garcia <ezequiel at vanguardiasur.com.ar>
> > ---
> >  drivers/gpu/drm/i915/intel_hdmi.c | 14 ++++++++++++++
> >  1 file changed, 14 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_hdmi.c
b/drivers/gpu/drm/i915/intel_hdmi.c
> > index a0d8daed2470..c079206e6681 100644
> > --- a/drivers/gpu/drm/i915/intel_hdmi.c
> > +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> > @@ -1428,6 +1428,20 @@ intel_hdmi_detect(struct drm_connector
*connector, bool force)
> >       } else
> >               status = connector_status_disconnected;
> >
> > +     /*
> > +      * The above call to intel_hdmi_set_edid() checked for a valid
EDID.
> > +      * However, the EDID can get corrupted for several reasons,
resulting
> > +      * in a disconnected status despite the connector being connected.
> > +      * Hence, let's try one more time, by only probing the DDC.
> > +      *
> > +      * This allows the DRM core to fallback to builtin or
user-provided
> > +      * EDID firmware, e.g. in drm_helper_probe_single_connector_modes.
> > +      */
> > +     if (status == connector_status_disconnected)
> > +             if (drm_probe_ddc(intel_gmbus_get_adapter(dev_priv,
> > +                                             intel_hdmi->ddc_bus)))
> > +                     status = connector_status_connected;
> > +
> >       intel_display_power_put(dev_priv, POWER_DOMAIN_GMBUS);
> >
> >       return status;
> > --
> > 2.7.0
> >
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
> --
> Ville Syrjälä
> Intel OTC
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