[Freedreno] [PATCH v2] drm/msm: Change dpu_crtc_get_vblank_counter to use vsync count.

[abhinavk at codeaurora.org]

On 2021-08-30 11:13, Mark Yacoub wrote:
> From: Mark Yacoub <markyacoub at google.com>
> 
> [why]
> vsync_cnt atomic counter increments for every hw vsync. On the other
> hand, frame count is a register that increments when the frame gets
> actually pushed out. We cannnot read this register whenever the timing
> engine is off, but vblank counter should still return a valid number.
> This behavior also matches the downstream driver.
> 
> [How]
> Read the encoder vsync count instead of the dpu_encoder_phys frame
> count.
> 
> Suggested-by: Abhinav Kumar <abhinavk at codeaurora.org>
> CC: Rob Clark <robdclark at chromium.org>
> Signed-off-by: Mark Yacoub <markyacoub at chromium.org>

LGTM,
Reviewed-by: Abhinav Kumar <abhinavk at codeaurora.org>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c    |  8 +++-----
>  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 16 ++++------------
>  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h |  4 ++--
>  3 files changed, 9 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> index 9a5c70c87cc86..cfd426b6776e0 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> @@ -78,15 +78,13 @@ static struct drm_encoder
> *get_encoder_from_crtc(struct drm_crtc *crtc)
> 
>  static u32 dpu_crtc_get_vblank_counter(struct drm_crtc *crtc)
>  {
> -	struct drm_encoder *encoder;
> -
> -	encoder = get_encoder_from_crtc(crtc);
> +	struct drm_encoder *encoder = get_encoder_from_crtc(crtc);
>  	if (!encoder) {
>  		DRM_ERROR("no encoder found for crtc %d\n", crtc->index);
> -		return false;
> +		return 0;
>  	}
> 
> -	return dpu_encoder_get_frame_count(encoder);
> +	return dpu_encoder_get_vsync_count(encoder);
>  }
> 
>  static bool dpu_crtc_get_scanout_position(struct drm_crtc *crtc,
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> index 1c04b7cce43e3..41d5643327709 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> @@ -397,19 +397,11 @@ int dpu_encoder_helper_unregister_irq(struct
> dpu_encoder_phys *phys_enc,
>  	return 0;
>  }
> 
> -int dpu_encoder_get_frame_count(struct drm_encoder *drm_enc)
> +int dpu_encoder_get_vsync_count(struct drm_encoder *drm_enc)
>  {
> -	struct dpu_encoder_virt *dpu_enc;
> -	struct dpu_encoder_phys *phys;
> -	int framecount = 0;
> -
> -	dpu_enc = to_dpu_encoder_virt(drm_enc);
> -	phys = dpu_enc ? dpu_enc->cur_master : NULL;
> -
> -	if (phys && phys->ops.get_frame_count)
> -		framecount = phys->ops.get_frame_count(phys);
> -
> -	return framecount;
> +	struct dpu_encoder_virt *dpu_enc = to_dpu_encoder_virt(drm_enc);
> +	struct dpu_encoder_phys *phys = dpu_enc ? dpu_enc->cur_master : NULL;
> +	return phys ? atomic_read(&phys->vsync_cnt) : 0;
>  }
> 
>  int dpu_encoder_get_linecount(struct drm_encoder *drm_enc)
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> index 99a5d73c9b886..e241914a96777 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> @@ -163,9 +163,9 @@ void dpu_encoder_set_idle_timeout(struct
> drm_encoder *drm_enc,
>  int dpu_encoder_get_linecount(struct drm_encoder *drm_enc);
> 
>  /**
> - * dpu_encoder_get_frame_count - get interface frame count for the 
> encoder.
> + * dpu_encoder_get_vsync_count - get vsync count for the encoder.
>   * @drm_enc:    Pointer to previously created drm encoder structure
>   */
> -int dpu_encoder_get_frame_count(struct drm_encoder *drm_enc);
> +int dpu_encoder_get_vsync_count(struct drm_encoder *drm_enc);
> 
>  #endif /* __DPU_ENCODER_H__ */