Maybe when the cable is disconnected the DP phy should be shutdown and
some bit in the phy could effectively "cut off" the aux channel and then
NAKs would start coming through here in the DP controller I/O register
space. This patch have DP aux channel read/write to return NAK immediately
if DP controller connection status is in unplugged state.
Changes in V4:
-- split this patch as stand alone patch
Signed-off-by: Kuogee Hsieh <khsieh@xxxxxxxxxxxxxx>
---
drivers/gpu/drm/msm/dp/dp_aux.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c
index 7c22bfe..fae3806 100644
--- a/drivers/gpu/drm/msm/dp/dp_aux.c
+++ b/drivers/gpu/drm/msm/dp/dp_aux.c
@@ -343,6 +343,11 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
mutex_lock(&aux->mutex);
+ if (!dp_catalog_link_is_connected(aux->catalog)) {
+ ret = -ETIMEDOUT;
+ goto unlock_exit;
+ }
+
aux->native = msg->request & (DP_AUX_NATIVE_WRITE & DP_AUX_NATIVE_READ);
/* Ignore address only message */
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
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