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-rw-r--r--drivers/gpu/drm/i915/intel_sdvo.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index d522a62c4dbb..29e21d32f9ce 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -1638,6 +1638,32 @@ intel_sdvo_hdmi_sink_detect(struct drm_connector *connector, u16 response)
edid = drm_get_edid(&intel_output->base,
intel_output->ddc_bus);
+ /* This is only applied to SDVO cards with multiple outputs */
+ if (edid == NULL && intel_sdvo_multifunc_encoder(intel_output)) {
+ uint8_t saved_ddc, temp_ddc;
+ saved_ddc = sdvo_priv->ddc_bus;
+ temp_ddc = sdvo_priv->ddc_bus >> 1;
+ /*
+ * Don't use the 1 as the argument of DDC bus switch to get
+ * the EDID. It is used for SDVO SPD ROM.
+ */
+ while(temp_ddc > 1) {
+ sdvo_priv->ddc_bus = temp_ddc;
+ edid = drm_get_edid(&intel_output->base,
+ intel_output->ddc_bus);
+ if (edid) {
+ /*
+ * When we can get the EDID, maybe it is the
+ * correct DDC bus. Update it.
+ */
+ sdvo_priv->ddc_bus = temp_ddc;
+ break;
+ }
+ temp_ddc >>= 1;
+ }
+ if (edid == NULL)
+ sdvo_priv->ddc_bus = saved_ddc;
+ }
/* when there is no edid and no monitor is connected with VGA
* port, try to use the CRT ddc to read the EDID for DVI-connector
*/