Re: [PATCH v5 04/15] drm/msm/dp: split msm_dp_ctrl_config_ctrl() into link parts and stream parts

[Yongxing Mou <yongxing.mou@oss.qualcomm.com>]

On 5/28/2026 11:22 PM, Dmitry Baryshkov wrote:
> On Thu, May 28, 2026 at 06:40:25PM +0800, Yongxing Mou wrote:
>> The DP_CONFIGURATION_CTRL register contains both link-level and
>> stream-specific fields. Currently, msm_dp_ctrl_config_ctrl() configures
>> all of them together. Separate the configuration into link parts and
>> stream parts to support MST.
>>
>> Signed-off-by: Yongxing Mou <yongxing.mou@oss.qualcomm.com>
>> ---
>>   drivers/gpu/drm/msm/dp/dp_ctrl.c | 47 +++++++++++++++++++++++++++-------------
>>   1 file changed, 32 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
>> index 86ef8c89ad44..cc00e8d2d6c7 100644
>> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
>> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
>> @@ -388,26 +388,45 @@ void msm_dp_ctrl_push_idle(struct msm_dp_ctrl *msm_dp_ctrl)
>>   	drm_dbg_dp(ctrl->drm_dev, "mainlink off\n");
>>   }
>>   
>> -static void msm_dp_ctrl_config_ctrl(struct msm_dp_ctrl_private *ctrl)
>> +static void msm_dp_ctrl_config_ctrl_streams(struct msm_dp_ctrl_private *ctrl,
>> +					    struct msm_dp_panel *msm_dp_panel)
>>   {
>>   	u32 config = 0, tbd;
>> +
>> +	/*
>> +	 * RMW: in SST, config_ctrl_link and config_ctrl_streams are called
>> +	 * sequentially on the same thread. In MST, caller holds mst_lock.
> 
> There is neither MST nor mst_lock. Also being called on the same thread
> means nothing, there can be another thread, executing the same code
> concurretly. Please point out that they are called only from the
> atomic_enable() callback, which is guarantted to be executed once at a
> time.
> 
Got it.. Will fix it next patch.
>> +	 */
>> +	config = msm_dp_read_link(ctrl, REG_DP_CONFIGURATION_CTRL);
>