[Freedreno] [DPU PATCH v2 1/2] drm/msm/dsi: check video mode engine status before waiting

[abhinavk at codeaurora.org]

Hi Sean

Thanks for the review.

Reply inline.

On 2018-04-13 13:26, Sean Paul wrote:
> On Tue, Apr 10, 2018 at 06:54:06PM -0700, Abhinav Kumar wrote:
>> Make sure the video mode engine is on before waiting
>> for the video done interrupt.
>> 
>> Otherwise it leads to silent timeouts increasing display
>> turn ON time.
>> 
>> Changes in v2:
>> - Replace pr_err with dev_err
>> - Changed error message
>> 
>> Signed-off-by: Abhinav Kumar <abhinavk at codeaurora.org>
>> ---
>>  drivers/gpu/drm/msm/dsi/dsi_host.c | 15 +++++++++++----
>>  1 file changed, 11 insertions(+), 4 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c 
>> b/drivers/gpu/drm/msm/dsi/dsi_host.c
>> index 7a03a94..5b7b290 100644
>> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
>> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
>> @@ -173,6 +173,7 @@ struct msm_dsi_host {
>> 
>>  	bool registered;
>>  	bool power_on;
>> +	bool enabled;
>>  	int irq;
>>  };
>> 
>> @@ -986,13 +987,19 @@ static void dsi_set_tx_power_mode(int mode, 
>> struct msm_dsi_host *msm_host)
>> 
>>  static void dsi_wait4video_done(struct msm_dsi_host *msm_host)
>>  {
>> +	u32 ret = 0;
>> +	struct device *dev = &msm_host->pdev->dev;
>> +
>>  	dsi_intr_ctrl(msm_host, DSI_IRQ_MASK_VIDEO_DONE, 1);
>> 
>>  	reinit_completion(&msm_host->video_comp);
>> 
>> -	wait_for_completion_timeout(&msm_host->video_comp,
>> +	ret = wait_for_completion_timeout(&msm_host->video_comp,
>>  			msecs_to_jiffies(70));
>> 
>> +	if (ret <= 0)
>> +		dev_err(dev, "wait for video done timed out\n");
>> +
>>  	dsi_intr_ctrl(msm_host, DSI_IRQ_MASK_VIDEO_DONE, 0);
>>  }
>> 
>> @@ -1001,7 +1008,7 @@ static void dsi_wait4video_eng_busy(struct 
>> msm_dsi_host *msm_host)
>>  	if (!(msm_host->mode_flags & MIPI_DSI_MODE_VIDEO))
>>  		return;
>> 
>> -	if (msm_host->power_on) {
>> +	if (msm_host->power_on && msm_host->enabled) {
>>  		dsi_wait4video_done(msm_host);
>>  		/* delay 4 ms to skip BLLP */
>>  		usleep_range(2000, 4000);
>> @@ -2203,7 +2210,7 @@ int msm_dsi_host_enable(struct mipi_dsi_host 
>> *host)
>>  	 *	pm_runtime_put_autosuspend(&msm_host->pdev->dev);
>>  	 * }
>>  	 */
>> -
>> +	msm_host->enabled = true;
>>  	return 0;
>>  }
>> 
>> @@ -2219,7 +2226,7 @@ int msm_dsi_host_disable(struct mipi_dsi_host 
>> *host)
>>  	 * Reset to disable video engine so that we can send off cmd.
>>  	 */
>>  	dsi_sw_reset(msm_host);
>> -
>> +	msm_host->enabled = false;
> 
> This should go at the start of the function. Also, it's unclear from 
> this patch,
> but I assume this is protected by a lock?
> 
> Sean
[Abhinav] Yes, will move this to the start.
No, there is no lock here but at this point doesnt need one.
The reason is that, this variable will be written to and read by the 
same process
(suspend thread OR resume thread which sends the panel ON/OFF commands).
If we decide to expose other interfaces to send commands like debugfs or 
sysfs and
introduce more threads, we will add the locking.
> 
> 
>>  	return 0;
>>  }
>> 
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora 
>> Forum,
>> a Linux Foundation Collaborative Project
>> 
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