From: Ville Syrjälä <ville.syrj...@linux.intel.com>

[ Upstream commit 7974033e527a5dd12d96126d09d4cff4f9b65c69 ]

CH7511 eDP->LVDS bridge doesn't seem to set SINK_COUNT properly
causing i915 to detect it as disconnected. Add a quirk to ignore
SINK_COUNT on these devices.

Cc: David S. <da...@majinbuu.com>
Cc: Peteris Rudzusiks <peteris.rudzus...@gmail.com>
Tested-by: Peteris Rudzusiks <peteris.rudzus...@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105406
Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com>
Link: 
https://patchwork.freedesktop.org/patch/msgid/20190528140650.19230-1-ville.syrj...@linux.intel.com
Acked-by: Jani Nikula <jani.nik...@intel.com> #irc
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 drivers/gpu/drm/drm_dp_helper.c | 4 +++-
 include/drm/drm_dp_helper.h     | 7 +++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 54a6414c5d961..429c58ce56ced 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -1278,7 +1278,9 @@ static const struct dpcd_quirk dpcd_quirk_list[] = {
        /* LG LP140WF6-SPM1 eDP panel */
        { OUI(0x00, 0x22, 0xb9), DEVICE_ID('s', 'i', 'v', 'a', 'r', 'T'), 
false, BIT(DP_DPCD_QUIRK_CONSTANT_N) },
        /* Apple panels need some additional handling to support PSR */
-       { OUI(0x00, 0x10, 0xfa), DEVICE_ID_ANY, false, 
BIT(DP_DPCD_QUIRK_NO_PSR) }
+       { OUI(0x00, 0x10, 0xfa), DEVICE_ID_ANY, false, 
BIT(DP_DPCD_QUIRK_NO_PSR) },
+       /* CH7511 seems to leave SINK_COUNT zeroed */
+       { OUI(0x00, 0x00, 0x00), DEVICE_ID('C', 'H', '7', '5', '1', '1'), 
false, BIT(DP_DPCD_QUIRK_NO_SINK_COUNT) },
 };
 
 #undef OUI
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 97ce790a5b5aa..d6c89cbe127a3 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -1401,6 +1401,13 @@ enum drm_dp_quirk {
         * driver still need to implement proper handling for such device.
         */
        DP_DPCD_QUIRK_NO_PSR,
+       /**
+        * @DP_DPCD_QUIRK_NO_SINK_COUNT:
+        *
+        * The device does not set SINK_COUNT to a non-zero value.
+        * The driver should ignore SINK_COUNT during detection.
+        */
+       DP_DPCD_QUIRK_NO_SINK_COUNT,
 };
 
 /**
-- 
2.20.1



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