> -----Original Message-----
> From: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> Sent: Monday, October 24, 2022 8:52 PM
> To: Vinod Polimera (QUIC) <quic_vpolimer@xxxxxxxxxxx>; dri-
> devel@xxxxxxxxxxxxxxxxxxxxx; linux-arm-msm@xxxxxxxxxxxxxxx;
> freedreno@xxxxxxxxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx; robdclark@xxxxxxxxx;
> dianders@xxxxxxxxxxxx; swboyd@xxxxxxxxxxxx; Kalyan Thota (QUIC)
> <quic_kalyant@xxxxxxxxxxx>; Kuogee Hsieh (QUIC)
> <quic_khsieh@xxxxxxxxxxx>; Vishnuvardhan Prodduturi (QUIC)
> <quic_vproddut@xxxxxxxxxxx>; Bjorn Andersson (QUIC)
> <quic_bjorande@xxxxxxxxxxx>; Aravind Venkateswaran (QUIC)
> <quic_aravindh@xxxxxxxxxxx>; Abhinav Kumar (QUIC)
> <quic_abhinavk@xxxxxxxxxxx>; Sankeerth Billakanti (QUIC)
> <quic_sbillaka@xxxxxxxxxxx>
> 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@xxxxxxxxxxx>
> > ---
> > 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.
