* [PATCH] drm/i915: Favor last VBT child device with conflicting AUX ch/DDC pin
@ 2019-10-11 20:20 Ville Syrjala
2019-10-14 8:16 ` Jani Nikula
0 siblings, 1 reply; 2+ messages in thread
From: Ville Syrjala @ 2019-10-11 20:20 UTC (permalink / raw)
To: intel-gfx; +Cc: stable, Jani Nikula, Masami Ichikawa, Torsten
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.
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;
}
--
2.21.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] drm/i915: Favor last VBT child device with conflicting AUX ch/DDC pin
2019-10-11 20:20 [PATCH] drm/i915: Favor last VBT child device with conflicting AUX ch/DDC pin Ville Syrjala
@ 2019-10-14 8:16 ` Jani Nikula
0 siblings, 0 replies; 2+ messages in thread
From: Jani Nikula @ 2019-10-14 8:16 UTC (permalink / raw)
To: Ville Syrjala, intel-gfx; +Cc: stable, Masami Ichikawa, Torsten
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;
> }
--
Jani Nikula, Intel Open Source Graphics Center
^ permalink raw reply [flat|nested] 2+ messages in thread
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