Re: [PATCH] drm/msm: dpu: Don't reset dpu_enc->cur_master on .disable()

[Jeykumar Sankaran <jsanka-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>]

On 2018-09-17 13:49, Sean Paul wrote:
> From: Sean Paul <seanpaul@chromium.org>
> 
> cur_master in dpu_encoder is assigned at modeset and cleared on
> .disable(). Unfortunately dpms (or enable/disable) does not guarantee a
> modeset, so cur_master is NULL when we try to re-enable it.
> 
> This patch moves the NULL assignment to setup_display where it will be
> re-assigned later in the function.
> 
The patch looks harmless to me. But the encoder->disable also calls 
.disable() on
the physical encoders. If the DPMS is not invoking an enable, why does
it need to access cur_master when all the physical encoders are in the 
disabled state?
Can we clean up the usage of cur_master if possible in the dpms path?

Thanks,
Jeykumar S.


> Signed-off-by: Sean Paul <seanpaul@chromium.org>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> index c2e8985b4c54..ae03d8d43b27 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> @@ -1230,8 +1230,6 @@ static void dpu_encoder_virt_disable(struct
> drm_encoder *drm_enc)
>  			dpu_enc->phys_encs[i]->connector = NULL;
>  	}
> 
> -	dpu_enc->cur_master = NULL;
> -
>  	DPU_DEBUG_ENC(dpu_enc, "encoder disabled\n");
> 
>  	dpu_rm_release(&dpu_kms->rm, drm_enc);
> @@ -2072,6 +2070,8 @@ static int dpu_encoder_setup_display(struct
> dpu_encoder_virt *dpu_enc,
>  		return -EINVAL;
>  	}
> 
> +	dpu_enc->cur_master = NULL;
> +
>  	memset(&phys_params, 0, sizeof(phys_params));
>  	phys_params.dpu_kms = dpu_kms;
>  	phys_params.parent = &dpu_enc->base;

-- 
Jeykumar S
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