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

[Sean Paul <seanpaul-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>]

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@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


>  	return 0;
>  }
>  
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
> 
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-- 
Sean Paul, Software Engineer, Google / Chromium OS
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