On Fri, 11 Oct 2019, Ville Syrjala ville.syrjala@linux.intel.com wrote:
From: Ville Syrjälä ville.syrjala@linux.intel.com
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@intel.com
Cc: stable@vger.kernel.org Cc: Jani Nikula jani.nikula@intel.com Cc: Masami Ichikawa masami256@gmail.com Tested-by: Torsten freedesktop201910@liggy.de 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@linux.intel.com
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; }