Re: [PATCH v7 01/15] drm/msm/disp/dpu: clear dpu_assign_crtc and get crtc from connector state instead of dpu_enc

[Dmitry Baryshkov]

On 13/09/2022 20:04, Dmitry Baryshkov wrote:
> On 13/09/2022 17:51, 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@xxxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c    |  4 ----
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 35 
> > ++++++++++++-----------------
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h |  8 -------
> >   3 files changed, 14 insertions(+), 33 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..0c7d8b5 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;
> > @@ -1288,6 +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;
> > +    struct drm_crtc *crtc;
> >       unsigned long lock_flags;
> >       if (!drm_enc || !phy_enc)
> > @@ -1298,9 +1293,14 @@ static void dpu_encoder_vblank_callback(struct 
> > drm_encoder *drm_enc,
> >       atomic_inc(&phy_enc->vsync_cnt);
> > +    if (!dpu_enc->connector || !dpu_enc->connector->state)
> > +        return;
> > +
> > +    crtc = dpu_enc->connector->state->crtc;
> > +
> >       spin_lock_irqsave(&dpu_enc->enc_spinlock, lock_flags);
> > -    if (dpu_enc->crtc)
> > -        dpu_crtc_vblank_callback(dpu_enc->crtc);
> > +    if (crtc)
> > +        dpu_crtc_vblank_callback(crtc);
> >       spin_unlock_irqrestore(&dpu_enc->enc_spinlock, lock_flags);
>
> Stephen's comment about reading the state from outside of the lock and 
> then using local variable under spinlock is still valid. Moreover I'm 
> not sure that enc_spinlock protects connector's state. I'd say one has 
> to take the modesetting lock here.

s/Stephen's/Doug's/

--
With best wishes
Dmitry