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

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

[Sean Paul]

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.

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

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

[Bruce Wang]

On Mon, Sep 17, 2018 at 4:50 PM Sean Paul <sean@poorly.run> 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.
>
> Signed-off-by: Sean Paul <seanpaul@chromium.org>

Tested-by: Bruce Wang <bzwang@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;
> --
> Sean Paul, Software Engineer, Google / Chromium OS
>
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Re: [PATCH] drm/msm: dpu: Don't reset dpu_enc->cur_master on .disable()

[Jeykumar Sankaran]

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

[Sean Paul]

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

> 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

-- 
Sean Paul, Software Engineer, Google / Chromium OS
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Re: [PATCH] drm/msm: dpu: Don't reset dpu_enc->cur_master on .disable()

[Jeykumar Sankaran]

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>

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

[Sean Paul]

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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