On Fri, 11 Oct 2019, Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > The first come first served apporoach to handling the VBT > child device AUX ch conflicts has backfired. We have machines > in the wild where the VBT specifies both port A eDP and > port E DP (in that order) with port E being the real one. > > So let's try to flip the preference around and let the last > child device win once again. I think there will be legitimate cases where we need first come first served. Oh well, another VBT misery to tackle in the future. Acked-by: Jani Nikula <jani.nikula@xxxxxxxxx> > > Cc: stable@xxxxxxxxxxxxxxx > Cc: Jani Nikula <jani.nikula@xxxxxxxxx> > Cc: Masami Ichikawa <masami256@xxxxxxxxx> > Tested-by: Torsten <freedesktop201910@xxxxxxxx> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111966 > Fixes: 36a0f92020dc ("drm/i915/bios: make child device order the priority order") > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > --- > drivers/gpu/drm/i915/display/intel_bios.c | 22 ++++++++++++++++------ > 1 file changed, 16 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c > index 9628b485b179..f0307b04cc13 100644 > --- a/drivers/gpu/drm/i915/display/intel_bios.c > +++ b/drivers/gpu/drm/i915/display/intel_bios.c > @@ -1270,7 +1270,7 @@ static void sanitize_ddc_pin(struct drm_i915_private *dev_priv, > DRM_DEBUG_KMS("port %c trying to use the same DDC pin (0x%x) as port %c, " > "disabling port %c DVI/HDMI support\n", > port_name(port), info->alternate_ddc_pin, > - port_name(p), port_name(port)); > + port_name(p), port_name(p)); > > /* > * If we have multiple ports supposedly sharing the > @@ -1278,9 +1278,14 @@ static void sanitize_ddc_pin(struct drm_i915_private *dev_priv, > * port. Otherwise they share the same ddc bin and > * system couldn't communicate with them separately. > * > - * Give child device order the priority, first come first > - * served. > + * 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 :( > */ > + info = &dev_priv->vbt.ddi_port_info[p]; > + > info->supports_dvi = false; > info->supports_hdmi = false; > info->alternate_ddc_pin = 0; > @@ -1316,7 +1321,7 @@ static void sanitize_aux_ch(struct drm_i915_private *dev_priv, > DRM_DEBUG_KMS("port %c trying to use the same AUX CH (0x%x) as port %c, " > "disabling port %c DP support\n", > port_name(port), info->alternate_aux_channel, > - port_name(p), port_name(port)); > + port_name(p), port_name(p)); > > /* > * If we have multiple ports supposedlt sharing the > @@ -1324,9 +1329,14 @@ static void sanitize_aux_ch(struct drm_i915_private *dev_priv, > * port. Otherwise they share the same aux channel > * and system couldn't communicate with them separately. > * > - * Give child device order the priority, first come first > - * served. > + * 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 :( > */ > + info = &dev_priv->vbt.ddi_port_info[p]; > + > info->supports_dp = false; > info->alternate_aux_channel = 0; > } -- Jani Nikula, Intel Open Source Graphics Center
