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authorZhao Yakui <yakui.zhao@intel.com>2010-01-08 10:58:20 +0800
committerGreg Kroah-Hartman <gregkh@suse.de>2010-01-25 10:49:39 -0800
commited0cd89c7333b17d50812201602f436b57ef1482 (patch)
tree1985ea9c69733c785df865e2ab30f0ef5cbd8b04
parent4fb77a3f85d3e4633e6ef3a8b319f882caf7c623 (diff)
downloadlinux-linaro-stable-ed0cd89c7333b17d50812201602f436b57ef1482.tar.gz
drm/i915: try another possible DDC bus for the SDVO device with multiple outputs
commit 7c3f0a2726fed78e0e0afe3b6fc3c1f5b298e447 upstream. There exist multiple DDC buses for the SDVO cards with multiple outputs. When we can't get the EDID by using the select DDC bus, we can try the other possible DDC bus to see whether the EDID can be obtained. https://bugs.freedesktop.org/show_bug.cgi?id=23842 Signed-off-by: Zhao Yakui <yakui.zhao@intel.com> Tested-by: Sebastien Caty <sebastien.caty@mrnf.gouv.qc.ca> Signed-off-by: Eric Anholt <eric@anholt.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-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
*/