lkml.org 
[lkml]   [2020]   [Oct]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] drm/msm/dp: skip checking LINK_STATUS_UPDATED bit
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;
>> }

\
 
 \ /
  Last update: 2020-10-30 23:07    [W:0.068 / U:0.040 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site