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drm/i915: Also check for VGA converter in eDP probe

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Unfortunately even the HPD based detection added in
commit cfe5bdfb27 ("drm/i915: Check HPD live state during eDP probe")
fails to detect that the VBT's eDP/DDI-A is a ghost on
Asus B360M-A (CFL+CNP). On that board eDP/DDI-A has its HPD
asserted despite nothing being actually connected there :(
The straps/fuses also indicate that the eDP port is present.

So if one boots with a VGA monitor connected the eDP probe will
mistake the DP->VGA converter hooked to DDI-E for an eDP panel
on DDI-A.

As a last resort check what kind of DP device we've detected,
and if it looks like a DP->VGA converter then conclude that
the eDP port should be ignored.

Cc: stable@vger.kernel.org
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/9636
Fixes: cfe5bdfb27 ("drm/i915: Check HPD live state during eDP probe")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231114142333.15799-1-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
(cherry picked from commit fcd479a791)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
This commit is contained in:
Ville Syrjälä 2023-11-14 16:23:33 +02:00 committed by Jani Nikula
parent 503579448d
commit f76f83a83c
1 changed files with 22 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
drivers/gpu/drm/i915/display/intel_dp.c
View File

@ -6037,8 +6037,7 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
* (eg. Acer Chromebook C710), so we'll check it only if multiple
* ports are attempting to use the same AUX CH, according to VBT.
*/
if (intel_bios_dp_has_shared_aux_ch(encoder->devdata) &&
!intel_digital_port_connected(encoder)) {
if (intel_bios_dp_has_shared_aux_ch(encoder->devdata)) {
/*
* If this fails, presume the DPCD answer came
* from some other port using the same AUX CH.
@ -6046,10 +6045,27 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
* FIXME maybe cleaner to check this before the
* DPCD read? Would need sort out the VDD handling...
*/
drm_info(&dev_priv->drm,
"[ENCODER:%d:%s] HPD is down, disabling eDP\n",
encoder->base.base.id, encoder->base.name);
goto out_vdd_off;
if (!intel_digital_port_connected(encoder)) {
drm_info(&dev_priv->drm,
"[ENCODER:%d:%s] HPD is down, disabling eDP\n",
encoder->base.base.id, encoder->base.name);
goto out_vdd_off;
}
/*
* Unfortunately even the HPD based detection fails on
* eg. Asus B360M-A (CFL+CNP), so as a last resort fall
* back to checking for a VGA branch device. Only do this
* on known affected platforms to minimize false positives.
*/
if (DISPLAY_VER(dev_priv) == 9 && drm_dp_is_branch(intel_dp->dpcd) &&
(intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_TYPE_MASK) ==
DP_DWN_STRM_PORT_TYPE_ANALOG) {
drm_info(&dev_priv->drm,
"[ENCODER:%d:%s] VGA converter detected, disabling eDP\n",
encoder->base.base.id, encoder->base.name);
goto out_vdd_off;
}
}
mutex_lock(&dev_priv->drm.mode_config.mutex);