[Intel-gfx] [RESEND v2 1/2] drm/i915: Add connector property to limit max bpc
Sripada, Radhakrishna
radhakrishna.sripada at intel.com
Fri Nov 10 19:47:46 UTC 2017
> -----Original Message-----
> From: Vivi, Rodrigo
> Sent: Thursday, November 9, 2017 1:25 PM
> To: Sripada, Radhakrishna <radhakrishna.sripada at intel.com>
> Cc: intel-gfx at lists.freedesktop.org; Zanoni, Paulo R
> <paulo.r.zanoni at intel.com>
> Subject: Re: [Intel-gfx] [RESEND v2 1/2] drm/i915: Add connector property to
> limit max bpc
>
> On Thu, Nov 09, 2017 at 12:31:51AM +0000, Radhakrishna Sripada wrote:
> > From: "Sripada, Radhakrishna" <radhakrishna.sripada at intel.com>
> >
> > At times 12bpc HDMI cannot be driven due to faulty cables, dongles
> > level shifters etc. To workaround them we may need to drive the output
> > at a lower bpc. Currently the user space does not have a way to limit
> > the bpc. The default bpc to be programmed is decided by the driver and
> > is run against connector limitations.
> >
> > Creating a new connector property "max bpc" in order to limit the bpc
> > with which the pixels are scanned out. xrandr can make use of this
> > connector property to make sure that bpc does not exceed the configured
> value.
>
> I wonder if this case qualifies to "Linux is not about choice"...
When we are dealing with faulty hardware like cables/dongles/level-shifters we would need a quirk
to try falling back to a lower bpc and drive the output. However we set the default to the maximum
possible value that the driver is anyway currently doing. Is there an alternative that you would suggest
in this case?
>
> Or all test cases we already have in place would cover all possible
> combinations in CI to avoid dealing with future regressions.
>
> >
> > V2: Initialize max_bpc to satisfy kms_properties
> >
> > Suggested-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
> > Cc: Manasi Navare <manasi.d.navare at intel.com>
> > Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada at intel.com>
> > ---
> > drivers/gpu/drm/i915/i915_drv.h | 1 +
> > drivers/gpu/drm/i915/intel_atomic.c | 7 +++++++
> > drivers/gpu/drm/i915/intel_drv.h | 2 ++
> > drivers/gpu/drm/i915/intel_hdmi.c | 11 +++++++++++
> > drivers/gpu/drm/i915/intel_modes.c | 19 +++++++++++++++++++
> > 5 files changed, 40 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_drv.h
> b/drivers/gpu/drm/i915/i915_drv.h
> > index fe93115c4caa..9642bc4b7a0b 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.h
> > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > @@ -2477,6 +2477,7 @@ struct drm_i915_private {
> >
> > struct drm_property *broadcast_rgb_property;
> > struct drm_property *force_audio_property;
> > + struct drm_property *max_bpc_property;
> >
> > /* hda/i915 audio component */
> > struct i915_audio_component *audio_component;
> > diff --git a/drivers/gpu/drm/i915/intel_atomic.c
> b/drivers/gpu/drm/i915/intel_atomic.c
> > index 36d4e635e4ce..d6d836ea1a7f 100644
> > --- a/drivers/gpu/drm/i915/intel_atomic.c
> > +++ b/drivers/gpu/drm/i915/intel_atomic.c
> > @@ -58,6 +58,8 @@ int
> intel_digital_connector_atomic_get_property(struct drm_connector
> *connector,
> > *val = intel_conn_state->force_audio;
> > else if (property == dev_priv->broadcast_rgb_property)
> > *val = intel_conn_state->broadcast_rgb;
> > + else if (property == dev_priv->max_bpc_property)
> > + *val = intel_conn_state->max_bpc;
> > else {
> > DRM_DEBUG_ATOMIC("Unknown property %s\n",
> property->name);
> > return -EINVAL;
> > @@ -95,6 +97,11 @@ int
> intel_digital_connector_atomic_set_property(struct drm_connector
> *connector,
> > return 0;
> > }
> >
> > + if (property == dev_priv->max_bpc_property) {
> > + intel_conn_state->max_bpc = val;
> > + return 0;
> > + }
> > +
> > DRM_DEBUG_ATOMIC("Unknown property %s\n", property-
> >name);
> > return -EINVAL;
> > }
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h
> b/drivers/gpu/drm/i915/intel_drv.h
> > index 00b488688042..9004a1ee1e99 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -340,6 +340,7 @@ struct intel_digital_connector_state {
> >
> > enum hdmi_force_audio force_audio;
> > int broadcast_rgb;
> > + int max_bpc;
> > };
> >
> > #define to_intel_digital_connector_state(x) container_of(x, struct
> intel_digital_connector_state, base)
> > @@ -1704,6 +1705,7 @@ int intel_ddc_get_modes(struct drm_connector
> *c, struct i2c_adapter *adapter);
> > void intel_attach_force_audio_property(struct drm_connector
> *connector);
> > void intel_attach_broadcast_rgb_property(struct drm_connector
> *connector);
> > void intel_attach_aspect_ratio_property(struct drm_connector
> *connector);
> > +void intel_attach_max_bpc_property(struct drm_connector *connector,
> int min, int max);
> >
> >
> > /* intel_overlay.c */
> > diff --git a/drivers/gpu/drm/i915/intel_hdmi.c
> b/drivers/gpu/drm/i915/intel_hdmi.c
> > index fa1c793a21ef..4a5dda8aa8c3 100644
> > --- a/drivers/gpu/drm/i915/intel_hdmi.c
> > +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> > @@ -1808,10 +1808,21 @@ static const struct drm_encoder_funcs
> intel_hdmi_enc_funcs = {
> > static void
> > intel_hdmi_add_properties(struct intel_hdmi *intel_hdmi, struct
> drm_connector *connector)
> > {
> > + struct drm_i915_private *dev_priv = to_i915(connector->dev);
> > +
> > intel_attach_force_audio_property(connector);
> > intel_attach_broadcast_rgb_property(connector);
> > intel_attach_aspect_ratio_property(connector);
> > connector->state->picture_aspect_ratio =
> HDMI_PICTURE_ASPECT_NONE;
> > +
> > + if ((IS_G4X(dev_priv) || IS_VALLEYVIEW(dev_priv) ||
> > + IS_CHERRYVIEW(dev_priv))) {
> > + intel_attach_max_bpc_property(connector, 8, 10);
> > + to_intel_digital_connector_state(connector->state)-
> >max_bpc = 10;
> > + } else if (INTEL_GEN(dev_priv) >= 5) {
> > + intel_attach_max_bpc_property(connector, 8, 12);
> > + to_intel_digital_connector_state(connector->state)-
> >max_bpc = 12;
> > + }
> > }
> >
> > /*
> > diff --git a/drivers/gpu/drm/i915/intel_modes.c
> b/drivers/gpu/drm/i915/intel_modes.c
> > index 4e43f873c889..8357e494e911 100644
> > --- a/drivers/gpu/drm/i915/intel_modes.c
> > +++ b/drivers/gpu/drm/i915/intel_modes.c
> > @@ -150,3 +150,22 @@ intel_attach_aspect_ratio_property(struct
> drm_connector *connector)
> > connector->dev-
> >mode_config.aspect_ratio_property,
> > DRM_MODE_PICTURE_ASPECT_NONE);
> > }
> > +
> > +void
> > +intel_attach_max_bpc_property(struct drm_connector *connector, int
> min, int max)
> > +{
> > + struct drm_device *dev = connector->dev;
> > + struct drm_i915_private *dev_priv = to_i915(dev);
> > + struct drm_property *prop;
> > +
> > + prop = dev_priv->max_bpc_property;
> > + if (prop == NULL) {
> > + prop = drm_property_create_range(dev, 0, "max bpc", min,
> max);
> > + if (prop == NULL)
> > + return;
> > +
> > + dev_priv->max_bpc_property = prop;
> > + }
> > +
> > + drm_object_attach_property(&connector->base, prop, max);
> > +}
> > --
> > 2.9.3
> >
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> > Intel-gfx at lists.freedesktop.org
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