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

[Sean Paul <sean-p7yTbzM4H96eqtR555YLDQ@public.gmane.org>]

On Tue, Oct 02, 2018 at 12:59:18PM -0700, Jeykumar Sankaran wrote:
> On 2018-10-02 12:17, Sean Paul wrote:
> > On Tue, Oct 02, 2018 at 11:09:47AM -0700, Jeykumar Sankaran wrote:
> > > 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?
> > 
> > DPMS is invoking enable, but cur_master is currently only set on modeset
> > which
> > isn't invoked on DPMS.
> > 
> > Sean
> > 
> Got it! Misread the commit text.
> 
> Reviewed-by: Jeykumar Sankaran <jsanka@codeaurora.org>

Awesome, thanks for your review. I've pushed to dpu-staging.

Sean

> 
> > > 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
> 
> -- 
> Jeykumar S

-- 
Sean Paul, Software Engineer, Google / Chromium OS
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