[PATCH v8 1/2] drm/msm/dp: dp_link_parse_sink_count() return immediately if aux read failed

[Kuogee Hsieh]

Add checking aux read/write status at both dp_link_parse_sink_count()
and dp_link_parse_sink_status_filed() to avoid long timeout delay if
dp aux read/write failed at timeout due to cable unplugged. Also make
sure dp controller had been initialized before start dpcd read and write.

Changes in V4:
-- split this patch as stand alone patch

Changes in v5:
-- rebase on msm-next branch

Changes in v6:
-- add more details commit text

Signed-off-by: Kuogee Hsieh <quic_khs...@quicinc.com>
Reviewed-by: Stephen Boyd <swb...@chromium.org>
Tested-by: Stephen Boyd <swb...@chromium.org>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 12 +++++++++---
 drivers/gpu/drm/msm/dp/dp_link.c    | 19 ++++++++++++++-----
 2 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c 
b/drivers/gpu/drm/msm/dp/dp_display.c
index 3d61459..0766752 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -692,9 +692,15 @@ static int dp_irq_hpd_handle(struct dp_display_private 
*dp, u32 data)
                return 0;
        }
 
-       ret = dp_display_usbpd_attention_cb(&dp->pdev->dev);
-       if (ret == -ECONNRESET) { /* cable unplugged */
-               dp->core_initialized = false;
+       /*
+        * dp core (ahb/aux clks) must be initialized before
+        * irq_hpd be handled
+        */
+       if (dp->core_initialized) {
+               ret = dp_display_usbpd_attention_cb(&dp->pdev->dev);
+               if (ret == -ECONNRESET) { /* cable unplugged */
+                       dp->core_initialized = false;
+               }
        }
        DRM_DEBUG_DP("hpd_state=%d\n", state);
 
diff --git a/drivers/gpu/drm/msm/dp/dp_link.c b/drivers/gpu/drm/msm/dp/dp_link.c
index a5bdfc5..d4d31e5 100644
--- a/drivers/gpu/drm/msm/dp/dp_link.c
+++ b/drivers/gpu/drm/msm/dp/dp_link.c
@@ -737,18 +737,25 @@ static int dp_link_parse_sink_count(struct dp_link 
*dp_link)
        return 0;
 }
 
-static void dp_link_parse_sink_status_field(struct dp_link_private *link)
+static int dp_link_parse_sink_status_field(struct dp_link_private *link)
 {
        int len = 0;
 
        link->prev_sink_count = link->dp_link.sink_count;
-       dp_link_parse_sink_count(&link->dp_link);
+       len = dp_link_parse_sink_count(&link->dp_link);
+       if (len < 0) {
+               DRM_ERROR("DP parse sink count failed\n");
+               return len;
+       }
 
        len = drm_dp_dpcd_read_link_status(link->aux,
                link->link_status);
-       if (len < DP_LINK_STATUS_SIZE)
+       if (len < DP_LINK_STATUS_SIZE) {
                DRM_ERROR("DP link status read failed\n");
-       dp_link_parse_request(link);
+               return len;
+       }
+
+       return dp_link_parse_request(link);
 }
 
 /**
@@ -1023,7 +1030,9 @@ int dp_link_process_request(struct dp_link *dp_link)
 
        dp_link_reset_data(link);
 
-       dp_link_parse_sink_status_field(link);
+       ret = dp_link_parse_sink_status_field(link);
+       if (ret)
+               return ret;
 
        if (link->request.test_requested == DP_TEST_LINK_EDID_READ) {
                dp_link->sink_request |= DP_TEST_LINK_EDID_READ;
-- 
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