[PATCH v5] 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.

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

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

Signed-off-by: Kuogee Hsieh 

Reviewed-by: Stephen Boyd 
Tested-by: Stephen Boyd 
---
 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;
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v5] drm/msm/dp: dp_link_parse_sink_count() return immediately if aux read failed

[Stephen Boyd]

Quoting Kuogee Hsieh (2021-12-08 09:41:02)
> 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.
>
> Changes in V4:
> -- split this patch as stand alone patch
>
> Changes in v5:
> -- rebase on msm-next branch
>
> Signed-off-by: Kuogee Hsieh 
>

Remove this newline please.

> Reviewed-by: Stephen Boyd 
> Tested-by: Stephen Boyd 
> ---
>  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) {

This part of the commit isn't described in the commit text. Can you add
some more details in the commit text about this?

> +   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);
>