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. 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; } -- 2.21.0
