RE: [PATCH] drm/vblank: Extract get_vblank_counter_and_timestamp()

["Kandpal, Suraj" <suraj.kandpal@intel.com>]

> Subject: [PATCH] drm/vblank: Extract get_vblank_counter_and_timestamp()
> 
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> We have three copies of the "read vblank counter and timestamp in a loop"
> code. Consolidate to a single a function.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

LGTM,
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>

> ---
>  drivers/gpu/drm/drm_vblank.c | 36 +++++++++++++++++++++---------------
>  1 file changed, 21 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
> index f78bf37f1e0a..f90fb2d13e42 100644
> --- a/drivers/gpu/drm/drm_vblank.c
> +++ b/drivers/gpu/drm/drm_vblank.c
> @@ -236,6 +236,21 @@ static u32 __get_vblank_counter(struct drm_device
> *dev, unsigned int pipe)
>  	return drm_vblank_no_hw_counter(dev, pipe);  }
> 
> +static bool get_vblank_counter_and_timestamp(struct drm_device *dev,
> unsigned int pipe,
> +					     u32 *cur_vblank, ktime_t
> *t_vblank,
> +					     bool in_vblank_irq)
> +{
> +	int count = DRM_TIMESTAMP_MAXRETRIES;
> +	bool rc;
> +
> +	do {
> +		*cur_vblank = __get_vblank_counter(dev, pipe);
> +		rc = drm_get_last_vbltimestamp(dev, pipe, t_vblank,
> in_vblank_irq);
> +	} while (*cur_vblank != __get_vblank_counter(dev, pipe) && --count >
> +0);
> +
> +	return rc;
> +}
> +
>  /*
>   * Reset the stored timestamp for the current vblank count to correspond
>   * to the last vblank occurred.
> @@ -250,7 +265,6 @@ static void drm_reset_vblank_timestamp(struct
> drm_device *dev, unsigned int pipe
>  	u32 cur_vblank;
>  	bool rc;
>  	ktime_t t_vblank;
> -	int count = DRM_TIMESTAMP_MAXRETRIES;
> 
>  	spin_lock(&dev->vblank_time_lock);
> 
> @@ -258,10 +272,8 @@ static void drm_reset_vblank_timestamp(struct
> drm_device *dev, unsigned int pipe
>  	 * sample the current counter to avoid random jumps
>  	 * when drm_vblank_enable() applies the diff
>  	 */
> -	do {
> -		cur_vblank = __get_vblank_counter(dev, pipe);
> -		rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, false);
> -	} while (cur_vblank != __get_vblank_counter(dev, pipe) && --count >
> 0);
> +	rc = get_vblank_counter_and_timestamp(dev, pipe, &cur_vblank,
> +					      &t_vblank, false);
> 
>  	/*
>  	 * Only reinitialize corresponding vblank timestamp if high-precision
> query @@ -299,7 +311,6 @@ static void drm_update_vblank_count(struct
> drm_device *dev, unsigned int pipe,
>  	u32 cur_vblank, diff;
>  	bool rc;
>  	ktime_t t_vblank;
> -	int count = DRM_TIMESTAMP_MAXRETRIES;
>  	int framedur_ns = vblank->framedur_ns;
>  	u32 max_vblank_count = drm_max_vblank_count(dev, pipe);
> 
> @@ -315,10 +326,8 @@ static void drm_update_vblank_count(struct
> drm_device *dev, unsigned int pipe,
>  	 * updating its hardware counter while we are retrieving the
>  	 * corresponding vblank timestamp.
>  	 */
> -	do {
> -		cur_vblank = __get_vblank_counter(dev, pipe);
> -		rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank,
> in_vblank_irq);
> -	} while (cur_vblank != __get_vblank_counter(dev, pipe) && --count >
> 0);
> +	rc = get_vblank_counter_and_timestamp(dev, pipe, &cur_vblank,
> +					      &t_vblank, in_vblank_irq);
> 
>  	if (max_vblank_count) {
>  		/* trust the hw counter when it's around */ @@ -1543,7
> +1552,6 @@ static void drm_vblank_restore(struct drm_device *dev, unsigned
> int pipe)
>  	int framedur_ns;
>  	u64 diff_ns;
>  	u32 cur_vblank, diff = 1;
> -	int count = DRM_TIMESTAMP_MAXRETRIES;
>  	u32 max_vblank_count = drm_max_vblank_count(dev, pipe);
> 
>  	if (drm_WARN_ON(dev, pipe >= dev->num_crtcs)) @@ -1558,10
> +1566,8 @@ static void drm_vblank_restore(struct drm_device *dev, unsigned
> int pipe)
>  		      "Cannot compute missed vblanks without frame
> duration\n");
>  	framedur_ns = vblank->framedur_ns;
> 
> -	do {
> -		cur_vblank = __get_vblank_counter(dev, pipe);
> -		drm_get_last_vbltimestamp(dev, pipe, &t_vblank, false);
> -	} while (cur_vblank != __get_vblank_counter(dev, pipe) && --count >
> 0);
> +	get_vblank_counter_and_timestamp(dev, pipe, &cur_vblank,
> +					 &t_vblank, false);
> 
>  	diff_ns = ktime_to_ns(ktime_sub(t_vblank, vblank->time));
>  	if (framedur_ns)
> --
> 2.52.0