On Wed, Jun 21, 2023 at 10:56:14AM +0300, Jani Nikula wrote:
> On Tue, 20 Jun 2023, Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx> wrote:
> > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> >
> > Stop with the VBT DDC pin sanitation, and instead just check
> > that the appropriate DDC pin is still available when initializing
> > a HDMI connector.
>
> Could be more verbose about the why here.
>
> > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/display/intel_bios.c | 69 ----------------------
> > drivers/gpu/drm/i915/display/intel_hdmi.c | 72 +++++++++++++++++++----
> > 2 files changed, 59 insertions(+), 82 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
> > index 34a397adbd6b..439ab5b3cbe5 100644
> > --- a/drivers/gpu/drm/i915/display/intel_bios.c
> > +++ b/drivers/gpu/drm/i915/display/intel_bios.c
> > @@ -2230,72 +2230,6 @@ static u8 map_ddc_pin(struct drm_i915_private *i915, u8 vbt_pin)
> > return 0;
> > }
> >
> > -static enum port get_port_by_ddc_pin(struct drm_i915_private *i915, u8 ddc_pin)
> > -{
> > - enum port port;
> > -
> > - if (!ddc_pin)
> > - return PORT_NONE;
> > -
> > - for_each_port(port) {
> > - const struct intel_bios_encoder_data *devdata =
> > - i915->display.vbt.ports[port];
> > -
> > - if (devdata && ddc_pin == devdata->child.ddc_pin)
> > - return port;
> > - }
> > -
> > - return PORT_NONE;
> > -}
> > -
> > -static void sanitize_ddc_pin(struct intel_bios_encoder_data *devdata,
> > - enum port port)
> > -{
> > - struct drm_i915_private *i915 = devdata->i915;
> > - struct child_device_config *child;
> > - u8 mapped_ddc_pin;
> > - enum port p;
> > -
> > - if (!devdata->child.ddc_pin)
> > - return;
> > -
> > - mapped_ddc_pin = map_ddc_pin(i915, devdata->child.ddc_pin);
> > - if (!intel_gmbus_is_valid_pin(i915, mapped_ddc_pin)) {
> > - drm_dbg_kms(&i915->drm,
> > - "Port %c has invalid DDC pin %d, "
> > - "sticking to defaults\n",
> > - port_name(port), mapped_ddc_pin);
> > - devdata->child.ddc_pin = 0;
> > - return;
> > - }
> > -
> > - p = get_port_by_ddc_pin(i915, devdata->child.ddc_pin);
> > - if (p == PORT_NONE)
> > - return;
> > -
> > - drm_dbg_kms(&i915->drm,
> > - "port %c trying to use the same DDC pin (0x%x) as port %c, "
> > - "disabling port %c DVI/HDMI support\n",
> > - port_name(port), mapped_ddc_pin,
> > - port_name(p), port_name(p));
> > -
> > - /*
> > - * If we have multiple ports supposedly sharing the pin, then dvi/hdmi
> > - * couldn't exist on the shared port. Otherwise they share the same ddc
> > - * pin and system couldn't communicate with them separately.
> > - *
> > - * Give inverse child device order the priority, last one wins. Yes,
> > - * there are real machines (eg. Asrock B250M-HDV) where VBT has both
> > - * port A and port E with the same AUX ch and we must pick port E :(
> > - */
>
> The priority order gets changed, right? Needs explanation.
>
> > - child = &i915->display.vbt.ports[p]->child;
> > -
> > - child->device_type &= ~DEVICE_TYPE_TMDS_DVI_SIGNALING;
> > - child->device_type |= DEVICE_TYPE_NOT_HDMI_OUTPUT;
> > -
> > - child->ddc_pin = 0;
> > -}
> > -
> > static enum port get_port_by_aux_ch(struct drm_i915_private *i915, u8 aux_ch)
> > {
> > enum port port;
> > @@ -2753,9 +2687,6 @@ static void parse_ddi_port(struct intel_bios_encoder_data *devdata)
> >
> > sanitize_device_type(devdata, port);
> >
> > - if (intel_bios_encoder_supports_dvi(devdata))
> > - sanitize_ddc_pin(devdata, port);
> > -
> > if (intel_bios_encoder_supports_dp(devdata))
> > sanitize_aux_ch(devdata, port);
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c
> > index 7ac5e6c5e00d..8d1c8abfcffa 100644
> > --- a/drivers/gpu/drm/i915/display/intel_hdmi.c
> > +++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
> > @@ -2880,21 +2880,12 @@ static u8 g4x_port_to_ddc_pin(struct drm_i915_private *dev_priv,
> > return ddc_pin;
> > }
> >
> > -static u8 intel_hdmi_ddc_pin(struct intel_encoder *encoder)
> > +static u8 intel_hdmi_default_ddc_pin(struct intel_encoder *encoder)
> > {
> > struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> > enum port port = encoder->port;
> > u8 ddc_pin;
> >
> > - ddc_pin = intel_bios_hdmi_ddc_pin(encoder->devdata);
> > - if (ddc_pin) {
> > - drm_dbg_kms(&dev_priv->drm,
> > - "[ENCODER:%d:%s] Using DDC pin 0x%x (VBT)\n",
> > - encoder->base.base.id, encoder->base.name,
> > - ddc_pin);
> > - return ddc_pin;
> > - }
> > -
> > if (IS_ALDERLAKE_S(dev_priv))
> > ddc_pin = adls_port_to_ddc_pin(dev_priv, port);
> > else if (INTEL_PCH_TYPE(dev_priv) >= PCH_DG1)
> > @@ -2916,10 +2907,62 @@ static u8 intel_hdmi_ddc_pin(struct intel_encoder *encoder)
> > else
> > ddc_pin = g4x_port_to_ddc_pin(dev_priv, port);
> >
> > - drm_dbg_kms(&dev_priv->drm,
> > - "[ENCODER:%d:%s] Using DDC pin 0x%x (platform default)\n",
> > + return ddc_pin;
> > +}
> > +
> > +static struct intel_encoder *
> > +get_encoder_by_ddc_pin(struct intel_encoder *encoder, u8 ddc_pin)
> > +{
> > + struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> > + struct intel_encoder *other;
> > +
> > + for_each_intel_encoder(&i915->drm, other) {
> > + if (other == encoder)
> > + continue;
> > +
> > + if (!intel_encoder_is_dig_port(other))
> > + continue;
> > +
> > + if (enc_to_dig_port(other)->hdmi.ddc_bus == ddc_pin)
> > + return other;
> > + }
> > +
> > + return NULL;
> > +}
> > +
> > +static u8 intel_hdmi_ddc_pin(struct intel_encoder *encoder)
> > +{
> > + struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> > + struct intel_encoder *other;
> > + const char *source;
> > + u8 ddc_pin;
> > +
> > + ddc_pin = intel_bios_hdmi_ddc_pin(encoder->devdata);
> > + source = "VBT";
> > +
> > + if (!ddc_pin) {
> > + ddc_pin = intel_hdmi_default_ddc_pin(encoder);
> > + source = "platform default";
> > + }
> > +
> > + if (!intel_gmbus_is_valid_pin(i915, ddc_pin)) {
> > + drm_dbg_kms(&i915->drm, "[ENCODER:%d:%s] Invalid DDC pin %d\n",
> > + encoder->base.base.id, encoder->base.name, ddc_pin);
> > + return 0;
> > + }
>
> The existing code checks the vbt ddc pin for validity, and if it's
> invalid, falls back to platform default.
>
> The above skips the platform default fallback if vbt has invalid but
> non-zero ddc pin.
>
> I'm not sure if it really matters, but at the very least deserves a
> mention in the commit message.
Right. That one is subtle enough detail that I missed it myself.
>
>
> BR,
> Jani.
>
>
> > +
> > + other = get_encoder_by_ddc_pin(encoder, ddc_pin);
> > + if (other) {
> > + drm_dbg_kms(&i915->drm, "[ENCODER:%d:%s] DDC pin %d already claimed by [ENCODER:%d:%s]\n",
> > + encoder->base.base.id, encoder->base.name, ddc_pin,
> > + other->base.base.id, other->base.name);
> > + return 0;
> > + }
> > +
> > + drm_dbg_kms(&i915->drm,
> > + "[ENCODER:%d:%s] Using DDC pin 0x%x (%s)\n",
> > encoder->base.base.id, encoder->base.name,
> > - ddc_pin);
> > + ddc_pin, source);
> >
> > return ddc_pin;
> > }
> > @@ -2990,6 +3033,9 @@ void intel_hdmi_init_connector(struct intel_digital_port *dig_port,
> > return;
> >
> > intel_hdmi->ddc_bus = intel_hdmi_ddc_pin(intel_encoder);
> > + if (!intel_hdmi->ddc_bus)
> > + return;
> > +
> > ddc = intel_gmbus_get_adapter(dev_priv, intel_hdmi->ddc_bus);
> >
> > drm_connector_init_with_ddc(dev, connector,
>
> --
> Jani Nikula, Intel Open Source Graphics Center
--
Ville Syrjälä
Intel
