[Intel-gfx] [PATCH] drm/i915: Fix the HDMI hot plug disconnection failure (v2)

[Guang Bai]

On Mon, 8 Oct 2018 22:35:34 +0800
Chris Chiu <chiu at endlessm.com> wrote:

> Thanks! I have no problem with this patch.

There are Fi.CI.BAT failures with the v2 (only with formatting fix
added) while the previous patch had passing results.
Now trying to identify why the failures happened with trybot
Thanks,
Guang

> 
> On Thu, Oct 4, 2018 at 2:08 AM Guang Bai <guang.bai at intel.com> wrote:
> 
> > On some platforms, slowly unplugging (wiggling) the HDMI cable makes
> > the kernel to believe the HDMI display still connected. This is
> > because the HDMI DDC lines are disconnected sometimes later after
> > the hot-plug interrupt triggered. Use the hot plug live states to
> > honor HDMI hot plug status in addtion to access the DDC channels.
> >
> > v2: Fix the formatting issue
> >
> > Cc: Jani Nikula <jani.nikula at intel.com>
> > Cc: Chris Chiu <chiu at endlessm.com>
> > Signed-off-by: Guang Bai <guang.bai at intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_hotplug.c | 32
> > +++++++++++++++++++++++++++++--- 1 file changed, 29 insertions(+),
> > 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_hotplug.c
> > b/drivers/gpu/drm/i915/intel_hotplug.c
> > index 648a13c..98ab1ab 100644
> > --- a/drivers/gpu/drm/i915/intel_hotplug.c
> > +++ b/drivers/gpu/drm/i915/intel_hotplug.c
> > @@ -246,17 +246,43 @@ static void
> > intel_hpd_irq_storm_reenable_work(struct work_struct *work)
> >         intel_runtime_pm_put(dev_priv);
> >  }
> >
> > +#define MAX_SHORT_PULSE_MS     100
> > +#define PORT_CHECK_LOOP_COUNT  3
> > +
> >  bool intel_encoder_hotplug(struct intel_encoder *encoder,
> >                            struct intel_connector *connector)
> >  {
> >         struct drm_device *dev = connector->base.dev;
> > -       enum drm_connector_status old_status;
> > +       enum drm_connector_status old_status, new_status;
> > +       enum hpd_pin pin = encoder->hpd_pin;
> > +       struct drm_i915_private *dev_priv =
> > to_i915(encoder->base.dev);
> > +       u32 count = 0;
> >
> >         WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
> >         old_status = connector->base.status;
> >
> > -       connector->base.status =
> > -               drm_helper_probe_detect(&connector->base, NULL,
> > false);
> > +       /*
> > +        * Set HDMI connection status based on hot-plug live states
> > and
> > +        * display probe results.
> > +        */
> > +       if ((encoder->type == INTEL_OUTPUT_HDMI ||
> > +            encoder->type == INTEL_OUTPUT_DDI) &&
> > +           dev_priv->hotplug.stats[pin].state == HPD_ENABLED) {
> > +               do {
> > +                       new_status = connector_status_disconnected;
> > +                       msleep(MAX_SHORT_PULSE_MS);
> > +
> > +                       if (intel_digital_port_connected(encoder))
> > +                               new_status =
> > drm_helper_probe_detect(&connector->base,
> > +
> > NULL, false);
> > +                       if (new_status ==
> > connector_status_connected)
> > +                               break;
> > +               } while (++count <= PORT_CHECK_LOOP_COUNT);
> > +               connector->base.status = new_status;
> > +       } else {
> > +               connector->base.status =
> > +                       drm_helper_probe_detect(&connector->base,
> > NULL, false);
> > +       }
> >
> >         if (old_status == connector->base.status)
> >                 return false;
> > --
> > 2.7.4
> >
> >