Currently, our implementation of drm_connector_funcs.detect is
based on getting a valid EDID.
This requirement makes the driver fail to detect connected
connectors in case of EDID corruption, which prevents from falling
back to modes provided by builtin or user-provided EDIDs.
Let's fix this by improving the detection, with a DDC probe,
if the current EDID-based detection failed.
Note that a better way of dealing with this could calling
drm_probe_ddc in drm_connector_funcs.detect, and do the
EDID full reading and parsing in drm_connector_helper_funcs.get_modes,
when it's actually needed.
However, this would be more invasive and thus more error-prone.
The current commit is an attempt to get some uninvasive fix,
and allow for easier backporting.
Signed-off-by: Ezequiel Garcia <ezequiel at vanguardiasur.com.ar>
---
drivers/gpu/drm/i915/intel_hdmi.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c
b/drivers/gpu/drm/i915/intel_hdmi.c
index a0d8daed2470..c079206e6681 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -1428,6 +1428,20 @@ intel_hdmi_detect(struct drm_connector *connector, bool
force)
} else
status = connector_status_disconnected;
+ /*
+ * The above call to intel_hdmi_set_edid() checked for a valid EDID.
+ * However, the EDID can get corrupted for several reasons, resulting
+ * in a disconnected status despite the connector being connected.
+ * Hence, let's try one more time, by only probing the DDC.
+ *
+ * This allows the DRM core to fallback to builtin or user-provided
+ * EDID firmware, e.g. in drm_helper_probe_single_connector_modes.
+ */
+ if (status == connector_status_disconnected)
+ if (drm_probe_ddc(intel_gmbus_get_adapter(dev_priv,
+ intel_hdmi->ddc_bus)))
+ status = connector_status_connected;
+
intel_display_power_put(dev_priv, POWER_DOMAIN_GMBUS);
return status;
--
2.7.0
