diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c index f899afd924b4..eaacfd0920df 100644 --- a/drivers/gpu/drm/i915/intel_sdvo.c +++ b/drivers/gpu/drm/i915/intel_sdvo.c @@ -1628,6 +1628,32 @@ 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 */