Update crtc retrieval from dpu_enc to dpu_enc connector state,
since new links get set as part of the dpu enc virt mode set.
The dpu_enc->crtc cache is no more needed, hence cleaning it as
part of this change.

Signed-off-by: Vinod Polimera <quic_vpolimer@quicinc.com>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c    |  4 ---
 drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 42 +++++++++--------------------
 drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h |  8 ------
 3 files changed, 13 insertions(+), 41 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
index 13ce321..8ec9a13 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
@@ -1029,7 +1029,6 @@ static void dpu_crtc_disable(struct drm_crtc *crtc,
 		 */
 		if (dpu_encoder_get_intf_mode(encoder) == INTF_MODE_VIDEO)
 			release_bandwidth = true;
-		dpu_encoder_assign_crtc(encoder, NULL);
 	}
 
 	/* wait for frame_event_done completion */
@@ -1099,9 +1098,6 @@ static void dpu_crtc_enable(struct drm_crtc *crtc,
 	trace_dpu_crtc_enable(DRMID(crtc), true, dpu_crtc);
 	dpu_crtc->enabled = true;
 
-	drm_for_each_encoder_mask(encoder, crtc->dev, crtc->state->encoder_mask)
-		dpu_encoder_assign_crtc(encoder, crtc);
-
 	/* Enable/restore vblank irq handling */
 	drm_crtc_vblank_on(crtc);
 }
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
index 9c6817b..d05b353 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
@@ -132,11 +132,6 @@ enum dpu_enc_rc_states {
  * @intfs_swapped:	Whether or not the phys_enc interfaces have been swapped
  *			for partial update right-only cases, such as pingpong
  *			split where virtual pingpong does not generate IRQs
- * @crtc:		Pointer to the currently assigned crtc. Normally you
- *			would use crtc->state->encoder_mask to determine the
- *			link between encoder/crtc. However in this case we need
- *			to track crtc in the disable() hook which is called
- *			_after_ encoder_mask is cleared.
  * @connector:		If a mode is set, cached pointer to the active connector
  * @crtc_kickoff_cb:		Callback into CRTC that will flush & start
  *				all CTL paths
@@ -181,7 +176,6 @@ struct dpu_encoder_virt {
 
 	bool intfs_swapped;
 
-	struct drm_crtc *crtc;
 	struct drm_connector *connector;
 
 	struct dentry *debugfs_root;
@@ -1288,7 +1282,7 @@ static void dpu_encoder_vblank_callback(struct drm_encoder *drm_enc,
 		struct dpu_encoder_phys *phy_enc)
 {
 	struct dpu_encoder_virt *dpu_enc = NULL;
-	unsigned long lock_flags;
+	struct drm_crtc *crtc;
 
 	if (!drm_enc || !phy_enc)
 		return;
@@ -1296,12 +1290,13 @@ static void dpu_encoder_vblank_callback(struct drm_encoder *drm_enc,
 	DPU_ATRACE_BEGIN("encoder_vblank_callback");
 	dpu_enc = to_dpu_encoder_virt(drm_enc);
 
-	atomic_inc(&phy_enc->vsync_cnt);
+	if (!dpu_enc->connector || !dpu_enc->connector->state ||
+	    !dpu_enc->connector->state->crtc)
+		return;
 
-	spin_lock_irqsave(&dpu_enc->enc_spinlock, lock_flags);
-	if (dpu_enc->crtc)
-		dpu_crtc_vblank_callback(dpu_enc->crtc);
-	spin_unlock_irqrestore(&dpu_enc->enc_spinlock, lock_flags);
+	atomic_inc(&phy_enc->vsync_cnt);
+	crtc = dpu_enc->connector->state->crtc;
+	dpu_crtc_vblank_callback(crtc);
 
 	DPU_ATRACE_END("encoder_vblank_callback");
 }
@@ -1324,33 +1319,22 @@ static void dpu_encoder_underrun_callback(struct drm_encoder *drm_enc,
 	DPU_ATRACE_END("encoder_underrun_callback");
 }
 
-void dpu_encoder_assign_crtc(struct drm_encoder *drm_enc, struct drm_crtc *crtc)
-{
-	struct dpu_encoder_virt *dpu_enc = to_dpu_encoder_virt(drm_enc);
-	unsigned long lock_flags;
-
-	spin_lock_irqsave(&dpu_enc->enc_spinlock, lock_flags);
-	/* crtc should always be cleared before re-assigning */
-	WARN_ON(crtc && dpu_enc->crtc);
-	dpu_enc->crtc = crtc;
-	spin_unlock_irqrestore(&dpu_enc->enc_spinlock, lock_flags);
-}
-
 void dpu_encoder_toggle_vblank_for_crtc(struct drm_encoder *drm_enc,
 					struct drm_crtc *crtc, bool enable)
 {
 	struct dpu_encoder_virt *dpu_enc = to_dpu_encoder_virt(drm_enc);
-	unsigned long lock_flags;
+	struct drm_crtc *new_crtc;
 	int i;
 
 	trace_dpu_enc_vblank_cb(DRMID(drm_enc), enable);
 
-	spin_lock_irqsave(&dpu_enc->enc_spinlock, lock_flags);
-	if (dpu_enc->crtc != crtc) {
-		spin_unlock_irqrestore(&dpu_enc->enc_spinlock, lock_flags);
+	if (!dpu_enc->connector || !dpu_enc->connector->state)
+		return;
+
+	new_crtc = dpu_enc->connector->state->crtc;
+	if (!new_crtc || new_crtc != crtc) {
 		return;
 	}
-	spin_unlock_irqrestore(&dpu_enc->enc_spinlock, lock_flags);
 
 	for (i = 0; i < dpu_enc->num_phys_encs; i++) {
 		struct dpu_encoder_phys *phys = dpu_enc->phys_encs[i];
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
index 9e7236e..eda5cd8 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
@@ -40,14 +40,6 @@ struct msm_display_info {
 };
 
 /**
- * dpu_encoder_assign_crtc - Link the encoder to the crtc it's assigned to
- * @encoder:	encoder pointer
- * @crtc:	crtc pointer
- */
-void dpu_encoder_assign_crtc(struct drm_encoder *encoder,
-			     struct drm_crtc *crtc);
-
-/**
  * dpu_encoder_toggle_vblank_for_crtc - Toggles vblank interrupts on or off if
  *	the encoder is assigned to the given crtc
  * @encoder:	encoder pointer
-- 
2.7.4

On 12/10/2022 15:02, Vinod Polimera wrote:
> Update crtc retrieval from dpu_enc to dpu_enc connector state,
> since new links get set as part of the dpu enc virt mode set.
> The dpu_enc->crtc cache is no more needed, hence cleaning it as
> part of this change.
> 
> Signed-off-by: Vinod Polimera <quic_vpolimer@quicinc.com>
> ---
>   drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c    |  4 ---
>   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 42 +++++++++--------------------
>   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h |  8 ------
>   3 files changed, 13 insertions(+), 41 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> index 13ce321..8ec9a13 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> @@ -1029,7 +1029,6 @@ static void dpu_crtc_disable(struct drm_crtc *crtc,
>   		 */
>   		if (dpu_encoder_get_intf_mode(encoder) == INTF_MODE_VIDEO)
>   			release_bandwidth = true;
> -		dpu_encoder_assign_crtc(encoder, NULL);
>   	}
>   
>   	/* wait for frame_event_done completion */
> @@ -1099,9 +1098,6 @@ static void dpu_crtc_enable(struct drm_crtc *crtc,
>   	trace_dpu_crtc_enable(DRMID(crtc), true, dpu_crtc);
>   	dpu_crtc->enabled = true;
>   
> -	drm_for_each_encoder_mask(encoder, crtc->dev, crtc->state->encoder_mask)
> -		dpu_encoder_assign_crtc(encoder, crtc);
> -
>   	/* Enable/restore vblank irq handling */
>   	drm_crtc_vblank_on(crtc);
>   }
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> index 9c6817b..d05b353 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> @@ -132,11 +132,6 @@ enum dpu_enc_rc_states {
>    * @intfs_swapped:	Whether or not the phys_enc interfaces have been swapped
>    *			for partial update right-only cases, such as pingpong
>    *			split where virtual pingpong does not generate IRQs
> - * @crtc:		Pointer to the currently assigned crtc. Normally you
> - *			would use crtc->state->encoder_mask to determine the
> - *			link between encoder/crtc. However in this case we need
> - *			to track crtc in the disable() hook which is called
> - *			_after_ encoder_mask is cleared.
>    * @connector:		If a mode is set, cached pointer to the active connector
>    * @crtc_kickoff_cb:		Callback into CRTC that will flush & start
>    *				all CTL paths
> @@ -181,7 +176,6 @@ struct dpu_encoder_virt {
>   
>   	bool intfs_swapped;
>   
> -	struct drm_crtc *crtc;
>   	struct drm_connector *connector;
>   
>   	struct dentry *debugfs_root;
> @@ -1288,7 +1282,7 @@ static void dpu_encoder_vblank_callback(struct drm_encoder *drm_enc,
>   		struct dpu_encoder_phys *phy_enc)
>   {
>   	struct dpu_encoder_virt *dpu_enc = NULL;
> -	unsigned long lock_flags;
> +	struct drm_crtc *crtc;
>   
>   	if (!drm_enc || !phy_enc)
>   		return;
> @@ -1296,12 +1290,13 @@ static void dpu_encoder_vblank_callback(struct drm_encoder *drm_enc,
>   	DPU_ATRACE_BEGIN("encoder_vblank_callback");
>   	dpu_enc = to_dpu_encoder_virt(drm_enc);
>   
> -	atomic_inc(&phy_enc->vsync_cnt);
> +	if (!dpu_enc->connector || !dpu_enc->connector->state ||
> +	    !dpu_enc->connector->state->crtc)
> +		return;
>   
> -	spin_lock_irqsave(&dpu_enc->enc_spinlock, lock_flags);
> -	if (dpu_enc->crtc)
> -		dpu_crtc_vblank_callback(dpu_enc->crtc);
> -	spin_unlock_irqrestore(&dpu_enc->enc_spinlock, lock_flags);
> +	atomic_inc(&phy_enc->vsync_cnt);
> +	crtc = dpu_enc->connector->state->crtc;
> +	dpu_crtc_vblank_callback(crtc);

So, what if the user commits the mode setting change on another CPU, 
while we are handling the vblank callback here? Can this happen?

>   
>   	DPU_ATRACE_END("encoder_vblank_callback");
>   }
-- 
With best wishes
Dmitry

> -----Original Message-----
> From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Sent: Monday, October 24, 2022 8:52 PM
> To: Vinod Polimera (QUIC) <quic_vpolimer@quicinc.com>; dri-
> devel@lists.freedesktop.org; linux-arm-msm@vger.kernel.org;
> freedreno@lists.freedesktop.org; devicetree@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org; robdclark@gmail.com;
> dianders@chromium.org; swboyd@chromium.org; Kalyan Thota (QUIC)
> <quic_kalyant@quicinc.com>; Kuogee Hsieh (QUIC)
> <quic_khsieh@quicinc.com>; Vishnuvardhan Prodduturi (QUIC)
> <quic_vproddut@quicinc.com>; Bjorn Andersson (QUIC)
> <quic_bjorande@quicinc.com>; Aravind Venkateswaran (QUIC)
> <quic_aravindh@quicinc.com>; Abhinav Kumar (QUIC)
> <quic_abhinavk@quicinc.com>; Sankeerth Billakanti (QUIC)
> <quic_sbillaka@quicinc.com>
> Subject: Re: [PATCH v8 01/15] drm/msm/disp/dpu: clear dpu_assign_crtc and
> get crtc from connector state instead of dpu_enc
> 
> WARNING: This email originated from outside of Qualcomm. Please be wary
> of any links or attachments, and do not enable macros.
> 
> On 12/10/2022 15:02, Vinod Polimera wrote:
> > Update crtc retrieval from dpu_enc to dpu_enc connector state,
> > since new links get set as part of the dpu enc virt mode set.
> > The dpu_enc->crtc cache is no more needed, hence cleaning it as
> > part of this change.
> >
> > Signed-off-by: Vinod Polimera <quic_vpolimer@quicinc.com>
> > ---
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c    |  4 ---
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 42 +++++++++---------
> -----------
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h |  8 ------
> >   3 files changed, 13 insertions(+), 41 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> > index 13ce321..8ec9a13 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> > @@ -1029,7 +1029,6 @@ static void dpu_crtc_disable(struct drm_crtc *crtc,
> >                */
> >               if (dpu_encoder_get_intf_mode(encoder) == INTF_MODE_VIDEO)
> >                       release_bandwidth = true;
> > -             dpu_encoder_assign_crtc(encoder, NULL);
> >       }
> >
> >       /* wait for frame_event_done completion */
> > @@ -1099,9 +1098,6 @@ static void dpu_crtc_enable(struct drm_crtc *crtc,
> >       trace_dpu_crtc_enable(DRMID(crtc), true, dpu_crtc);
> >       dpu_crtc->enabled = true;
> >
> > -     drm_for_each_encoder_mask(encoder, crtc->dev, crtc->state-
> >encoder_mask)
> > -             dpu_encoder_assign_crtc(encoder, crtc);
> > -
> >       /* Enable/restore vblank irq handling */
> >       drm_crtc_vblank_on(crtc);
> >   }
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > index 9c6817b..d05b353 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > @@ -132,11 +132,6 @@ enum dpu_enc_rc_states {
> >    * @intfs_swapped:  Whether or not the phys_enc interfaces have been
> swapped
> >    *                  for partial update right-only cases, such as pingpong
> >    *                  split where virtual pingpong does not generate IRQs
> > - * @crtc:            Pointer to the currently assigned crtc. Normally you
> > - *                   would use crtc->state->encoder_mask to determine the
> > - *                   link between encoder/crtc. However in this case we need
> > - *                   to track crtc in the disable() hook which is called
> > - *                   _after_ encoder_mask is cleared.
> >    * @connector:              If a mode is set, cached pointer to the active
> connector
> >    * @crtc_kickoff_cb:                Callback into CRTC that will flush & start
> >    *                          all CTL paths
> > @@ -181,7 +176,6 @@ struct dpu_encoder_virt {
> >
> >       bool intfs_swapped;
> >
> > -     struct drm_crtc *crtc;
> >       struct drm_connector *connector;
> >
> >       struct dentry *debugfs_root;
> > @@ -1288,7 +1282,7 @@ static void dpu_encoder_vblank_callback(struct
> drm_encoder *drm_enc,
> >               struct dpu_encoder_phys *phy_enc)
> >   {
> >       struct dpu_encoder_virt *dpu_enc = NULL;
> > -     unsigned long lock_flags;
> > +     struct drm_crtc *crtc;
> >
> >       if (!drm_enc || !phy_enc)
> >               return;
> > @@ -1296,12 +1290,13 @@ static void dpu_encoder_vblank_callback(struct
> drm_encoder *drm_enc,
> >       DPU_ATRACE_BEGIN("encoder_vblank_callback");
> >       dpu_enc = to_dpu_encoder_virt(drm_enc);
> >
> > -     atomic_inc(&phy_enc->vsync_cnt);
> > +     if (!dpu_enc->connector || !dpu_enc->connector->state ||
> > +         !dpu_enc->connector->state->crtc)
> > +             return;
> >
> > -     spin_lock_irqsave(&dpu_enc->enc_spinlock, lock_flags);
> > -     if (dpu_enc->crtc)
> > -             dpu_crtc_vblank_callback(dpu_enc->crtc);
> > -     spin_unlock_irqrestore(&dpu_enc->enc_spinlock, lock_flags);
> > +     atomic_inc(&phy_enc->vsync_cnt);
> > +     crtc = dpu_enc->connector->state->crtc;
> > +     dpu_crtc_vblank_callback(crtc);
> 
> So, what if the user commits the mode setting change on another CPU,
> while we are handling the vblank callback here? Can this happen?
> 
If user issues a commit on another CPU, it will wait in the drm_atomic_helper_swap_state
as drm_atomic_helper_commit_hw_done which does the complete_all(&commit->hw_done) 
for the current commit didn't finish yet.
> >
> >       DPU_ATRACE_END("encoder_vblank_callback");
> >   }
> --
> With best wishes
> Dmitry

Thanks,
Vinod P.

On 27/10/2022 16:34, Vinod Polimera wrote:
>> -----Original Message-----
>> From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>> Sent: Monday, October 24, 2022 8:52 PM
>> To: Vinod Polimera (QUIC) <quic_vpolimer@quicinc.com>; dri-
>> devel@lists.freedesktop.org; linux-arm-msm@vger.kernel.org;
>> freedreno@lists.freedesktop.org; devicetree@vger.kernel.org
>> Cc: linux-kernel@vger.kernel.org; robdclark@gmail.com;
>> dianders@chromium.org; swboyd@chromium.org; Kalyan Thota (QUIC)
>> <quic_kalyant@quicinc.com>; Kuogee Hsieh (QUIC)
>> <quic_khsieh@quicinc.com>; Vishnuvardhan Prodduturi (QUIC)
>> <quic_vproddut@quicinc.com>; Bjorn Andersson (QUIC)
>> <quic_bjorande@quicinc.com>; Aravind Venkateswaran (QUIC)
>> <quic_aravindh@quicinc.com>; Abhinav Kumar (QUIC)
>> <quic_abhinavk@quicinc.com>; Sankeerth Billakanti (QUIC)
>> <quic_sbillaka@quicinc.com>
>> Subject: Re: [PATCH v8 01/15] drm/msm/disp/dpu: clear dpu_assign_crtc and
>> get crtc from connector state instead of dpu_enc
>>
>> WARNING: This email originated from outside of Qualcomm. Please be wary
>> of any links or attachments, and do not enable macros.
>>
>> On 12/10/2022 15:02, Vinod Polimera wrote:
>>> Update crtc retrieval from dpu_enc to dpu_enc connector state,
>>> since new links get set as part of the dpu enc virt mode set.
>>> The dpu_enc->crtc cache is no more needed, hence cleaning it as
>>> part of this change.
>>>
>>> Signed-off-by: Vinod Polimera <quic_vpolimer@quicinc.com>
>>> ---
>>>    drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c    |  4 ---
>>>    drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 42 +++++++++---------
>> -----------
>>>    drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h |  8 ------
>>>    3 files changed, 13 insertions(+), 41 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>>> index 13ce321..8ec9a13 100644
>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>>> @@ -1029,7 +1029,6 @@ static void dpu_crtc_disable(struct drm_crtc *crtc,
>>>                 */
>>>                if (dpu_encoder_get_intf_mode(encoder) == INTF_MODE_VIDEO)
>>>                        release_bandwidth = true;
>>> -             dpu_encoder_assign_crtc(encoder, NULL);
>>>        }
>>>
>>>        /* wait for frame_event_done completion */
>>> @@ -1099,9 +1098,6 @@ static void dpu_crtc_enable(struct drm_crtc *crtc,
>>>        trace_dpu_crtc_enable(DRMID(crtc), true, dpu_crtc);
>>>        dpu_crtc->enabled = true;
>>>
>>> -     drm_for_each_encoder_mask(encoder, crtc->dev, crtc->state-
>>> encoder_mask)
>>> -             dpu_encoder_assign_crtc(encoder, crtc);
>>> -
>>>        /* Enable/restore vblank irq handling */
>>>        drm_crtc_vblank_on(crtc);
>>>    }
>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>>> index 9c6817b..d05b353 100644
>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>>> @@ -132,11 +132,6 @@ enum dpu_enc_rc_states {
>>>     * @intfs_swapped:  Whether or not the phys_enc interfaces have been
>> swapped
>>>     *                  for partial update right-only cases, such as pingpong
>>>     *                  split where virtual pingpong does not generate IRQs
>>> - * @crtc:            Pointer to the currently assigned crtc. Normally you
>>> - *                   would use crtc->state->encoder_mask to determine the
>>> - *                   link between encoder/crtc. However in this case we need
>>> - *                   to track crtc in the disable() hook which is called
>>> - *                   _after_ encoder_mask is cleared.
>>>     * @connector:              If a mode is set, cached pointer to the active
>> connector
>>>     * @crtc_kickoff_cb:                Callback into CRTC that will flush & start
>>>     *                          all CTL paths
>>> @@ -181,7 +176,6 @@ struct dpu_encoder_virt {
>>>
>>>        bool intfs_swapped;
>>>
>>> -     struct drm_crtc *crtc;
>>>        struct drm_connector *connector;
>>>
>>>        struct dentry *debugfs_root;
>>> @@ -1288,7 +1282,7 @@ static void dpu_encoder_vblank_callback(struct
>> drm_encoder *drm_enc,
>>>                struct dpu_encoder_phys *phy_enc)
>>>    {
>>>        struct dpu_encoder_virt *dpu_enc = NULL;
>>> -     unsigned long lock_flags;
>>> +     struct drm_crtc *crtc;
>>>
>>>        if (!drm_enc || !phy_enc)
>>>                return;
>>> @@ -1296,12 +1290,13 @@ static void dpu_encoder_vblank_callback(struct
>> drm_encoder *drm_enc,
>>>        DPU_ATRACE_BEGIN("encoder_vblank_callback");
>>>        dpu_enc = to_dpu_encoder_virt(drm_enc);
>>>
>>> -     atomic_inc(&phy_enc->vsync_cnt);
>>> +     if (!dpu_enc->connector || !dpu_enc->connector->state ||
>>> +         !dpu_enc->connector->state->crtc)
>>> +             return;
>>>
>>> -     spin_lock_irqsave(&dpu_enc->enc_spinlock, lock_flags);
>>> -     if (dpu_enc->crtc)
>>> -             dpu_crtc_vblank_callback(dpu_enc->crtc);
>>> -     spin_unlock_irqrestore(&dpu_enc->enc_spinlock, lock_flags);
>>> +     atomic_inc(&phy_enc->vsync_cnt);
>>> +     crtc = dpu_enc->connector->state->crtc;
>>> +     dpu_crtc_vblank_callback(crtc);
>>
>> So, what if the user commits the mode setting change on another CPU,
>> while we are handling the vblank callback here? Can this happen?
>>
> If user issues a commit on another CPU, it will wait in the drm_atomic_helper_swap_state
> as drm_atomic_helper_commit_hw_done which does the complete_all(&commit->hw_done)
> for the current commit didn't finish yet.

Yes. But there is no interlock between commit->hw_done and vblank IRQ 
processing, isn't it? This call happens when DPU processes the vblank 
IRQ, so nobody stops other core from swapping the encode state on 
another core.

>>>
>>>        DPU_ATRACE_END("encoder_vblank_callback");
>>>    }
>> --
>> With best wishes
>> Dmitry
> 
> Thanks,
> Vinod P.

-- 
With best wishes
Dmitry

> -----Original Message-----
> From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Sent: Thursday, October 27, 2022 11:11 PM
> To: Vinod Polimera <vpolimer@qti.qualcomm.com>; Vinod Polimera (QUIC)
> <quic_vpolimer@quicinc.com>; dri-devel@lists.freedesktop.org; linux-arm-
> msm@vger.kernel.org; freedreno@lists.freedesktop.org;
> devicetree@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org; robdclark@gmail.com;
> dianders@chromium.org; swboyd@chromium.org; Kalyan Thota (QUIC)
> <quic_kalyant@quicinc.com>; Kuogee Hsieh (QUIC)
> <quic_khsieh@quicinc.com>; Vishnuvardhan Prodduturi (QUIC)
> <quic_vproddut@quicinc.com>; Bjorn Andersson (QUIC)
> <quic_bjorande@quicinc.com>; Aravind Venkateswaran (QUIC)
> <quic_aravindh@quicinc.com>; Abhinav Kumar (QUIC)
> <quic_abhinavk@quicinc.com>; Sankeerth Billakanti (QUIC)
> <quic_sbillaka@quicinc.com>
> Subject: Re: [PATCH v8 01/15] drm/msm/disp/dpu: clear dpu_assign_crtc and
> get crtc from connector state instead of dpu_enc
> 
> WARNING: This email originated from outside of Qualcomm. Please be wary
> of any links or attachments, and do not enable macros.
> 
> On 27/10/2022 16:34, Vinod Polimera wrote:
> >> -----Original Message-----
> >> From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> >> Sent: Monday, October 24, 2022 8:52 PM
> >> To: Vinod Polimera (QUIC) <quic_vpolimer@quicinc.com>; dri-
> >> devel@lists.freedesktop.org; linux-arm-msm@vger.kernel.org;
> >> freedreno@lists.freedesktop.org; devicetree@vger.kernel.org
> >> Cc: linux-kernel@vger.kernel.org; robdclark@gmail.com;
> >> dianders@chromium.org; swboyd@chromium.org; Kalyan Thota (QUIC)
> >> <quic_kalyant@quicinc.com>; Kuogee Hsieh (QUIC)
> >> <quic_khsieh@quicinc.com>; Vishnuvardhan Prodduturi (QUIC)
> >> <quic_vproddut@quicinc.com>; Bjorn Andersson (QUIC)
> >> <quic_bjorande@quicinc.com>; Aravind Venkateswaran (QUIC)
> >> <quic_aravindh@quicinc.com>; Abhinav Kumar (QUIC)
> >> <quic_abhinavk@quicinc.com>; Sankeerth Billakanti (QUIC)
> >> <quic_sbillaka@quicinc.com>
> >> Subject: Re: [PATCH v8 01/15] drm/msm/disp/dpu: clear dpu_assign_crtc
> and
> >> get crtc from connector state instead of dpu_enc
> >>
> >> WARNING: This email originated from outside of Qualcomm. Please be
> wary
> >> of any links or attachments, and do not enable macros.
> >>
> >> On 12/10/2022 15:02, Vinod Polimera wrote:
> >>> Update crtc retrieval from dpu_enc to dpu_enc connector state,
> >>> since new links get set as part of the dpu enc virt mode set.
> >>> The dpu_enc->crtc cache is no more needed, hence cleaning it as
> >>> part of this change.
> >>>
> >>> Signed-off-by: Vinod Polimera <quic_vpolimer@quicinc.com>
> >>> ---
> >>>    drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c    |  4 ---
> >>>    drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 42 +++++++++-----
> ----
> >> -----------
> >>>    drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h |  8 ------
> >>>    3 files changed, 13 insertions(+), 41 deletions(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> >> b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> >>> index 13ce321..8ec9a13 100644
> >>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> >>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> >>> @@ -1029,7 +1029,6 @@ static void dpu_crtc_disable(struct drm_crtc
> *crtc,
> >>>                 */
> >>>                if (dpu_encoder_get_intf_mode(encoder) ==
> INTF_MODE_VIDEO)
> >>>                        release_bandwidth = true;
> >>> -             dpu_encoder_assign_crtc(encoder, NULL);
> >>>        }
> >>>
> >>>        /* wait for frame_event_done completion */
> >>> @@ -1099,9 +1098,6 @@ static void dpu_crtc_enable(struct drm_crtc
> *crtc,
> >>>        trace_dpu_crtc_enable(DRMID(crtc), true, dpu_crtc);
> >>>        dpu_crtc->enabled = true;
> >>>
> >>> -     drm_for_each_encoder_mask(encoder, crtc->dev, crtc->state-
> >>> encoder_mask)
> >>> -             dpu_encoder_assign_crtc(encoder, crtc);
> >>> -
> >>>        /* Enable/restore vblank irq handling */
> >>>        drm_crtc_vblank_on(crtc);
> >>>    }
> >>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> >> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> >>> index 9c6817b..d05b353 100644
> >>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> >>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> >>> @@ -132,11 +132,6 @@ enum dpu_enc_rc_states {
> >>>     * @intfs_swapped:  Whether or not the phys_enc interfaces have
> been
> >> swapped
> >>>     *                  for partial update right-only cases, such as pingpong
> >>>     *                  split where virtual pingpong does not generate IRQs
> >>> - * @crtc:            Pointer to the currently assigned crtc. Normally you
> >>> - *                   would use crtc->state->encoder_mask to determine the
> >>> - *                   link between encoder/crtc. However in this case we need
> >>> - *                   to track crtc in the disable() hook which is called
> >>> - *                   _after_ encoder_mask is cleared.
> >>>     * @connector:              If a mode is set, cached pointer to the active
> >> connector
> >>>     * @crtc_kickoff_cb:                Callback into CRTC that will flush & start
> >>>     *                          all CTL paths
> >>> @@ -181,7 +176,6 @@ struct dpu_encoder_virt {
> >>>
> >>>        bool intfs_swapped;
> >>>
> >>> -     struct drm_crtc *crtc;
> >>>        struct drm_connector *connector;
> >>>
> >>>        struct dentry *debugfs_root;
> >>> @@ -1288,7 +1282,7 @@ static void
> dpu_encoder_vblank_callback(struct
> >> drm_encoder *drm_enc,
> >>>                struct dpu_encoder_phys *phy_enc)
> >>>    {
> >>>        struct dpu_encoder_virt *dpu_enc = NULL;
> >>> -     unsigned long lock_flags;
> >>> +     struct drm_crtc *crtc;
> >>>
> >>>        if (!drm_enc || !phy_enc)
> >>>                return;
> >>> @@ -1296,12 +1290,13 @@ static void
> dpu_encoder_vblank_callback(struct
> >> drm_encoder *drm_enc,
> >>>        DPU_ATRACE_BEGIN("encoder_vblank_callback");
> >>>        dpu_enc = to_dpu_encoder_virt(drm_enc);
> >>>
> >>> -     atomic_inc(&phy_enc->vsync_cnt);
> >>> +     if (!dpu_enc->connector || !dpu_enc->connector->state ||
> >>> +         !dpu_enc->connector->state->crtc)
> >>> +             return;
> >>>
> >>> -     spin_lock_irqsave(&dpu_enc->enc_spinlock, lock_flags);
> >>> -     if (dpu_enc->crtc)
> >>> -             dpu_crtc_vblank_callback(dpu_enc->crtc);
> >>> -     spin_unlock_irqrestore(&dpu_enc->enc_spinlock, lock_flags);
> >>> +     atomic_inc(&phy_enc->vsync_cnt);
> >>> +     crtc = dpu_enc->connector->state->crtc;
> >>> +     dpu_crtc_vblank_callback(crtc);
> >>
> >> So, what if the user commits the mode setting change on another CPU,
> >> while we are handling the vblank callback here? Can this happen?
> >>
> > If user issues a commit on another CPU, it will wait in the
> drm_atomic_helper_swap_state
> > as drm_atomic_helper_commit_hw_done which does the
> complete_all(&commit->hw_done)
> > for the current commit didn't finish yet.
> 
> Yes. But there is no interlock between commit->hw_done and vblank IRQ
> processing, isn't it? This call happens when DPU processes the vblank
> IRQ, so nobody stops other core from swapping the encode state on
> another core.

https://patchwork.kernel.org/project/linux-arm-msm/patch/1667300361-14572-1-git-send-email-quic_kalyant@quicinc.com/
(drm/msm/disp/dpu1: register crtc color management to first crtc in the list)

The above patch pins 1 crtc to 1 encoder, so it will be safe to assume that crtc wont change.

> >>>
> >>>        DPU_ATRACE_END("encoder_vblank_callback");
> >>>    }
> >> --
> >> With best wishes
> >> Dmitry
> >
> > Thanks,
> > Vinod P.
> 
> --
> With best wishes
> Dmitry

Thanks,
Vinod P.