On Mon, Nov 12, 2018 at 05:43:17PM -0800, Jeykumar Sankaran wrote:
> On 2018-11-12 11:42, Sean Paul wrote:
> > From: Sean Paul <seanpaul@xxxxxxxxxxxx>
> >
> > Add a bool to dpu_encoder_virt to track whether the encoder is enabled
> > or not. Repurpose the enc_lock mutex to ensure that it is consistent
> > with the hw state.
> >
> > Signed-off-by: Sean Paul <seanpaul@xxxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 27 +++++++++++++++++----
> > 1 file changed, 22 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > index 10a0676d1dcf..3daa86220d47 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > @@ -132,6 +132,7 @@ enum dpu_enc_rc_states {
> > * @base: drm_encoder base class for registration with DRM
> > * @enc_spinlock: Virtual-Encoder-Wide Spin Lock for IRQ purposes
> > * @bus_scaling_client: Client handle to the bus scaling interface
> > + * @enabled: True if the encoder is active, protected by
> > enc_lock
> > * @num_phys_encs: Actual number of physical encoders contained.
> > * @phys_encs: Container of physical encoders managed.
> > * @cur_master: Pointer to the current master in this
> > mode. Optimization
> > @@ -148,8 +149,8 @@ enum dpu_enc_rc_states {
> > * all CTL paths
> > * @crtc_kickoff_cb_data: Opaque user data given to crtc_kickoff_cb
> > * @debugfs_root: Debug file system root file node
> > - * @enc_lock: Lock around physical encoder
> > create/destroy and
> > - access.
> > + * @enc_lock: Lock around physical encoder
> > + * create/destroy/enable/disable
> > * @frame_busy_mask: Bitmask tracking which phys_enc we are
> > still
> > * busy processing current command.
> > * Bit0 = phys_encs[0] etc.
> > @@ -175,6 +176,8 @@ struct dpu_encoder_virt {
> > spinlock_t enc_spinlock;
> > uint32_t bus_scaling_client;
> >
> > + bool enabled;
> > +
> > unsigned int num_phys_encs;
> > struct dpu_encoder_phys *phys_encs[MAX_PHYS_ENCODERS_PER_VIRTUAL];
> > struct dpu_encoder_phys *cur_master;
> > @@ -1121,6 +1124,8 @@ static void dpu_encoder_virt_enable(struct
> > drm_encoder *drm_enc)
> > return;
> > }
> > dpu_enc = to_dpu_encoder_virt(drm_enc);
> > +
> > + mutex_lock(&dpu_enc->enc_lock);
> > cur_mode = &dpu_enc->base.crtc->state->adjusted_mode;
> >
> > trace_dpu_enc_enable(DRMID(drm_enc), cur_mode->hdisplay,
> > @@ -1137,10 +1142,15 @@ static void dpu_encoder_virt_enable(struct
> > drm_encoder *drm_enc)
> > if (ret) {
> > DPU_ERROR_ENC(dpu_enc, "dpu resource control failed:
> > %d\n",
> > ret);
> > - return;
> > + goto out;
> > }
> >
> > _dpu_encoder_virt_enable_helper(drm_enc);
> > +
> > + dpu_enc->enabled = true;
> > +
> > +out:
> > + mutex_unlock(&dpu_enc->enc_lock);
> > }
> >
> > static void dpu_encoder_virt_disable(struct drm_encoder *drm_enc)
> > @@ -1162,11 +1172,14 @@ static void dpu_encoder_virt_disable(struct
> > drm_encoder *drm_enc)
> > return;
> > }
> >
> > - mode = &drm_enc->crtc->state->adjusted_mode;
> > -
> > dpu_enc = to_dpu_encoder_virt(drm_enc);
> > DPU_DEBUG_ENC(dpu_enc, "\n");
> >
> > + mutex_lock(&dpu_enc->enc_lock);
> Where do you expect it to go wrong if enable/disable
> is not protected using enc_lock?
runtime_resume can run concurrently with either enable or disable. We need the
enc_lock to ensure that enable/disable/runtime_resume are all relatively atomic.
Sean
>
> Thanks and Regards,
> Jeykumar S.
> > + dpu_enc->enabled = false;
> > +
> > + mode = &drm_enc->crtc->state->adjusted_mode;
> > +
> > priv = drm_enc->dev->dev_private;
> > dpu_kms = to_dpu_kms(priv->kms);
> >
> > @@ -1200,6 +1213,8 @@ static void dpu_encoder_virt_disable(struct
> > drm_encoder *drm_enc)
> > DPU_DEBUG_ENC(dpu_enc, "encoder disabled\n");
> >
> > dpu_rm_release(&dpu_kms->rm, drm_enc);
> > +
> > + mutex_unlock(&dpu_enc->enc_lock);
> > }
> >
> > static enum dpu_intf dpu_encoder_get_intf(struct dpu_mdss_cfg *catalog,
> > @@ -2233,6 +2248,8 @@ struct drm_encoder *dpu_encoder_init(struct
> > drm_device *dev,
> >
> > drm_encoder_helper_add(&dpu_enc->base, &dpu_encoder_helper_funcs);
> >
> > + dpu_enc->enabled = false;
> > +
> > return &dpu_enc->base;
> > }
>
> --
> Jeykumar S
--
Sean Paul, Software Engineer, Google / Chromium OS
