diff mbox series

drm/msm/dp: skip checking LINK_STATUS_UPDATED bit

Message ID 20201020165959.7441-1-khsieh@codeaurora.org (mailing list archive)
State New, archived
Headers show
Series drm/msm/dp: skip checking LINK_STATUS_UPDATED bit | expand

Commit Message

Kuogee Hsieh Oct. 20, 2020, 4:59 p.m. UTC 
No need to check LINK_STATuS_UPDATED bit before
return 6 bytes of link status during link training.
This patch also fix phy compliance test link rate
conversion error.

Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
---
 drivers/gpu/drm/msm/dp/dp_ctrl.c | 20 ++++++--------------
 drivers/gpu/drm/msm/dp/dp_link.c | 24 +++++++++++-------------
 2 files changed, 17 insertions(+), 27 deletions(-)


base-commit: 0855cb4b31953b8c539e57b970da8146bcd4405a

Comments

Stephen Boyd Oct. 20, 2020, 10:15 p.m. UTC | #1 
Quoting Kuogee Hsieh (2020-10-20 09:59:59)
> No need to check LINK_STATuS_UPDATED bit before

LINK_STATUS_UPDATED?

> return 6 bytes of link status during link training.

Why?

> This patch also fix phy compliance test link rate
> conversion error.

How?

> 
> Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
> ---

Any Fixes: tag?

>  drivers/gpu/drm/msm/dp/dp_ctrl.c | 20 ++++++--------------
>  drivers/gpu/drm/msm/dp/dp_link.c | 24 +++++++++++-------------
>  2 files changed, 17 insertions(+), 27 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> index 6bdaec778c4c..76e891c91c6e 100644
> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> @@ -1061,23 +1061,15 @@ static bool dp_ctrl_train_pattern_set(struct dp_ctrl_private *ctrl,
>  static int dp_ctrl_read_link_status(struct dp_ctrl_private *ctrl,
>                                     u8 *link_status)
>  {
> -       int len = 0;
> -       u32 const offset = DP_LANE_ALIGN_STATUS_UPDATED - DP_LANE0_1_STATUS;
> -       u32 link_status_read_max_retries = 100;
> -
> -       while (--link_status_read_max_retries) {
> -               len = drm_dp_dpcd_read_link_status(ctrl->aux,
> -                       link_status);
> -               if (len != DP_LINK_STATUS_SIZE) {
> -                       DRM_ERROR("DP link status read failed, err: %d\n", len);
> -                       return len;
> -               }
> +       int ret = 0, len;
>  
> -               if (!(link_status[offset] & DP_LINK_STATUS_UPDATED))
> -                       return 0;
> +       len = drm_dp_dpcd_read_link_status(ctrl->aux, link_status);
> +       if (len != DP_LINK_STATUS_SIZE) {
> +               DRM_ERROR("DP link status read failed, err: %d\n", len);
> +               ret = len;

Could this be positive if the len is greater than 0 but not
DP_LINK_STATUS_SIZE? Maybe the check should be len < 0? We certainly
don't want to return some smaller size from this function, right?

>         }
>  
> -       return -ETIMEDOUT;
> +       return ret;
>  }
>  
>  static int dp_ctrl_link_train_1(struct dp_ctrl_private *ctrl,
> diff --git a/drivers/gpu/drm/msm/dp/dp_link.c b/drivers/gpu/drm/msm/dp/dp_link.c
> index c811da515fb3..58d65daae3b3 100644
> --- a/drivers/gpu/drm/msm/dp/dp_link.c
> +++ b/drivers/gpu/drm/msm/dp/dp_link.c
> @@ -773,7 +773,8 @@ static int dp_link_process_link_training_request(struct dp_link_private *link)
>                         link->request.test_lane_count);
>  
>         link->dp_link.link_params.num_lanes = link->request.test_lane_count;
> -       link->dp_link.link_params.rate = link->request.test_link_rate;
> +       link->dp_link.link_params.rate =
> +               drm_dp_bw_code_to_link_rate(link->request.test_link_rate);

Why are we storing bw_code in test_link_rate? This looks very confusing.

>  
>         return 0;
>  }
Kuogee Hsieh Oct. 30, 2020, 10:06 p.m. UTC | #2 
On 2020-10-20 15:15, Stephen Boyd wrote:
> Quoting Kuogee Hsieh (2020-10-20 09:59:59)
>> No need to check LINK_STATuS_UPDATED bit before
> 
> LINK_STATUS_UPDATED?
> 
>> return 6 bytes of link status during link training.
> 
> Why?
> 
>> This patch also fix phy compliance test link rate
>> conversion error.
> 
> How?
> 
>> 
>> Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
>> ---
> 
> Any Fixes: tag?
> 
>>  drivers/gpu/drm/msm/dp/dp_ctrl.c | 20 ++++++--------------
>>  drivers/gpu/drm/msm/dp/dp_link.c | 24 +++++++++++-------------
>>  2 files changed, 17 insertions(+), 27 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c 
>> b/drivers/gpu/drm/msm/dp/dp_ctrl.c
>> index 6bdaec778c4c..76e891c91c6e 100644
>> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
>> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
>> @@ -1061,23 +1061,15 @@ static bool dp_ctrl_train_pattern_set(struct 
>> dp_ctrl_private *ctrl,
>>  static int dp_ctrl_read_link_status(struct dp_ctrl_private *ctrl,
>>                                     u8 *link_status)
>>  {
>> -       int len = 0;
>> -       u32 const offset = DP_LANE_ALIGN_STATUS_UPDATED - 
>> DP_LANE0_1_STATUS;
>> -       u32 link_status_read_max_retries = 100;
>> -
>> -       while (--link_status_read_max_retries) {
>> -               len = drm_dp_dpcd_read_link_status(ctrl->aux,
>> -                       link_status);
>> -               if (len != DP_LINK_STATUS_SIZE) {
>> -                       DRM_ERROR("DP link status read failed, err: 
>> %d\n", len);
>> -                       return len;
>> -               }
>> +       int ret = 0, len;
>> 
>> -               if (!(link_status[offset] & DP_LINK_STATUS_UPDATED))
>> -                       return 0;
>> +       len = drm_dp_dpcd_read_link_status(ctrl->aux, link_status);
>> +       if (len != DP_LINK_STATUS_SIZE) {
>> +               DRM_ERROR("DP link status read failed, err: %d\n", 
>> len);
>> +               ret = len;
> 
> Could this be positive if the len is greater than 0 but not
> DP_LINK_STATUS_SIZE? Maybe the check should be len < 0? We certainly
> don't want to return some smaller size from this function, right?
> 

no, it should be exactly the byte number requested to read.
otherwise, it should be failed and will re read at next run.

>>         }
>> 
>> -       return -ETIMEDOUT;
>> +       return ret;
>>  }
>> 
>>  static int dp_ctrl_link_train_1(struct dp_ctrl_private *ctrl,
>> diff --git a/drivers/gpu/drm/msm/dp/dp_link.c 
>> b/drivers/gpu/drm/msm/dp/dp_link.c
>> index c811da515fb3..58d65daae3b3 100644
>> --- a/drivers/gpu/drm/msm/dp/dp_link.c
>> +++ b/drivers/gpu/drm/msm/dp/dp_link.c
>> @@ -773,7 +773,8 @@ static int 
>> dp_link_process_link_training_request(struct dp_link_private *link)
>>                         link->request.test_lane_count);
>> 
>>         link->dp_link.link_params.num_lanes = 
>> link->request.test_lane_count;
>> -       link->dp_link.link_params.rate = link->request.test_link_rate;
>> +       link->dp_link.link_params.rate =
>> +               
>> drm_dp_bw_code_to_link_rate(link->request.test_link_rate);
> 
> Why are we storing bw_code in test_link_rate? This looks very 
> confusing.

Test_link_rate contains link rate from dpcd read. it need to be convert 
to real
rate by timing 2.7Mb before start phy compliance test.

> 
>> 
>>         return 0;
>>  }
diff mbox series

Patch

diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index 6bdaec778c4c..76e891c91c6e 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -1061,23 +1061,15 @@  static bool dp_ctrl_train_pattern_set(struct dp_ctrl_private *ctrl,
 static int dp_ctrl_read_link_status(struct dp_ctrl_private *ctrl,
 				    u8 *link_status)
 {
-	int len = 0;
-	u32 const offset = DP_LANE_ALIGN_STATUS_UPDATED - DP_LANE0_1_STATUS;
-	u32 link_status_read_max_retries = 100;
-
-	while (--link_status_read_max_retries) {
-		len = drm_dp_dpcd_read_link_status(ctrl->aux,
-			link_status);
-		if (len != DP_LINK_STATUS_SIZE) {
-			DRM_ERROR("DP link status read failed, err: %d\n", len);
-			return len;
-		}
+	int ret = 0, len;
 
-		if (!(link_status[offset] & DP_LINK_STATUS_UPDATED))
-			return 0;
+	len = drm_dp_dpcd_read_link_status(ctrl->aux, link_status);
+	if (len != DP_LINK_STATUS_SIZE) {
+		DRM_ERROR("DP link status read failed, err: %d\n", len);
+		ret = len;
 	}
 
-	return -ETIMEDOUT;
+	return ret;
 }
 
 static int dp_ctrl_link_train_1(struct dp_ctrl_private *ctrl,
diff --git a/drivers/gpu/drm/msm/dp/dp_link.c b/drivers/gpu/drm/msm/dp/dp_link.c
index c811da515fb3..58d65daae3b3 100644
--- a/drivers/gpu/drm/msm/dp/dp_link.c
+++ b/drivers/gpu/drm/msm/dp/dp_link.c
@@ -773,7 +773,8 @@  static int dp_link_process_link_training_request(struct dp_link_private *link)
 			link->request.test_lane_count);
 
 	link->dp_link.link_params.num_lanes = link->request.test_lane_count;
-	link->dp_link.link_params.rate = link->request.test_link_rate;
+	link->dp_link.link_params.rate =
+		drm_dp_bw_code_to_link_rate(link->request.test_link_rate);
 
 	return 0;
 }
@@ -939,20 +940,17 @@  static u8 get_link_status(const u8 link_status[DP_LINK_STATUS_SIZE], int r)
  */
 static int dp_link_process_link_status_update(struct dp_link_private *link)
 {
-	if (!(get_link_status(link->link_status,
-				DP_LANE_ALIGN_STATUS_UPDATED) &
-				DP_LINK_STATUS_UPDATED) ||
-			(drm_dp_clock_recovery_ok(link->link_status,
-					link->dp_link.link_params.num_lanes) &&
-			drm_dp_channel_eq_ok(link->link_status,
-					link->dp_link.link_params.num_lanes)))
-		return -EINVAL;
+	bool channel_eq_done = drm_dp_channel_eq_ok(link->link_status,
+			link->dp_link.link_params.num_lanes);
+
+	bool clock_recovery_done = drm_dp_clock_recovery_ok(link->link_status,
+			link->dp_link.link_params.num_lanes);
 
 	DRM_DEBUG_DP("channel_eq_done = %d, clock_recovery_done = %d\n",
-			drm_dp_clock_recovery_ok(link->link_status,
-			link->dp_link.link_params.num_lanes),
-			drm_dp_clock_recovery_ok(link->link_status,
-			link->dp_link.link_params.num_lanes));
+			channel_eq_done, clock_recovery_done);
+
+	if (channel_eq_done && clock_recovery_done)
+		return -EINVAL;
 
 	return 0;
 }