linux-kernel - Re: [PATCH v2] drm/msm/dpu: drop validity checks for clear_pending

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Date: Thu, 20 Jun 2024 22:59:58 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Abhinav Kumar <quic_abhinavk@...cinc.com>
Cc: freedreno@...ts.freedesktop.org, Rob Clark <robdclark@...il.com>, 
	Sean Paul <sean@...rly.run>, Marijn Suijten <marijn.suijten@...ainline.org>, 
	David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>, dri-devel@...ts.freedesktop.org, 
	quic_jesszhan@...cinc.com, dan.carpenter@...aro.org, linux-arm-msm@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] drm/msm/dpu: drop validity checks for
 clear_pending_flush() ctl op

On Thu, Jun 20, 2024 at 12:12:27PM GMT, Abhinav Kumar wrote:
> clear_pending_flush() ctl op is always assigned irrespective of the DPU
> hardware revision. Hence there is no needed to check whether the op has
> been assigned before calling it.
> 
> Drop the checks across the driver for clear_pending_flush() and also
> update its documentation that it is always expected to be assigned.
> 
> changes in v2:
> 	- instead of adding more validity checks just drop the one for clear_pending_flush
> 	- update the documentation for clear_pending_flush() ctl op
> 	- update the commit text reflecting these changes
> 
> Fixes: d7d0e73f7de3 ("drm/msm/dpu: introduce the dpu_encoder_phys_* for writeback")
> Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
> Closes: https://lore.kernel.org/all/464fbd84-0d1c-43c3-a40b-31656ac06456@moroto.mountain/T/
> Signed-off-by: Abhinav Kumar <quic_abhinavk@...cinc.com>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c         | 3 +--
>  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c | 3 +--
>  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.h          | 4 +++-
>  3 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.h
> index ef56280bea93..6f8c7ffa2d27 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.h
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.h
> @@ -83,7 +83,9 @@ struct dpu_hw_ctl_ops {
>  
>  	/**
>  	 * Clear the value of the cached pending_flush_mask
> -	 * No effect on hardware
> +	 * No effect on hardware. This ctl op is always assigned
> +	 * irrespective of hw version and hence no check is needed
> +	 * for the callers to check its availability before calling it.

A simple 'Required to be imlemented' or just 'Required' should be enough.

>  	 * @ctx       : ctl path ctx pointer
>  	 */
>  	void (*clear_pending_flush)(struct dpu_hw_ctl *ctx);
> -- 
> 2.44.0
> 

-- 
With best wishes
Dmitry