On Wed, Nov 14, 2018 at 11:33:53AM -0800, Jeykumar Sankaran wrote:
> On 2018-11-14 07:13, Sean Paul wrote:
> > On Tue, Nov 13, 2018 at 04:47:22PM -0800, Jeykumar Sankaran wrote:
> > > On 2018-11-13 12:52, Sean Paul wrote:
> > > > From: Sean Paul <seanpaul@xxxxxxxxxxxx>
> > > >
> > > > The indirection of registering a callback and opaque pointer isn't
> > real
> > > > useful when there's only one callsite. So instead of having the
> > > > vblank_cb registration, just give encoder a crtc and let it directly
> > > > call the vblank handler.
> > > >
> > > > In a later patch, we'll make use of this further.
> > > >
> > > > Signed-off-by: Sean Paul <seanpaul@xxxxxxxxxxxx>
> > > > ---
> > > > drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 8 +++----
> > > > drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h | 6 +++++
> > > > drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 25
> > +++++++++++----------
> > > > drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h | 10 ++++-----
> > > > 4 files changed, 26 insertions(+), 23 deletions(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> > > > b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> > > > index adda0aa0cbaa..38119b4d4a80 100644
> > > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> > > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> > > > @@ -291,9 +291,8 @@ enum dpu_intf_mode dpu_crtc_get_intf_mode(struct
> > > > drm_crtc *crtc)
> > > > return INTF_MODE_NONE;
> > > > }
> > > >
> > > > -static void dpu_crtc_vblank_cb(void *data)
> > > > +void dpu_crtc_vblank_callback(struct drm_crtc *crtc)
> > > > {
> > > > - struct drm_crtc *crtc = (struct drm_crtc *)data;
> > > > struct dpu_crtc *dpu_crtc = to_dpu_crtc(crtc);
> > >
> > > Since we are calling into a locally stored CRTC and not tracking
> > disable.
> > > Should
> > > we check for crtc->enable before processing the callback?
> > >
> > > I see vblank_on/off cant be called when CRTC is disabled with the rest
> > > of the patches in the series. But this callback is triggered by IRQ's
> > > context.
> >
> > Hmm, yeah, I had assumed that we wouldn't have any interrupts after irq
> > disable.
> > However it doesn't seem like that's the case.
> >
> > That said, I don't think checking crtc->enable is quite what we want. In
> > the
> > case of disable, the crtc is cleared from the encoder, so checking for
> > crtc != NULL would be better here. SGTY?
> That would still cause a race as crtc assignment will be protected by
> modeset
> locks and crtc != NULL check isn't.
Right, we'd need to wrap the callback in the encoder spinlock.
> >
> > Now that I've dug into the vblank irq handling a bit in the encoder, it
> > seems
> > like that could be moved to the crtc and a bunch of the
> > encoder->crtc->encoder
> > bouncing around could be avoided. Off the top of your head, is there any
> > reason
> > we couldn't move the vblank irq handling into crtc from encoder?
> vblank irq handlers are only needed for video mode. As with all the other
> IRQ's, the handlers are implemented in phys_encoder level and the events
> are forwarded as and when needed.
>
I took a look at how that might work, and it seems possible but probably not
worthwhile.
Sean
> BTW, the vblank irq flows from phys_enc->virtual_enc->crtc.
>
> Thanks,
> Jeykumar S.
>
> >
> > Sean
> >
> > >
> > > >
> > > > /* keep statistics on vblank callback - with auto reset via
> > > > debugfs */
> > > > @@ -779,8 +778,7 @@ static void _dpu_crtc_vblank_enable_no_lock(
> > > > DRMID(enc), enable,
> > > > dpu_crtc);
> > > >
> > > > - dpu_encoder_register_vblank_callback(enc,
> > > > - dpu_crtc_vblank_cb, (void *)crtc);
> > > > + dpu_encoder_assign_crtc(enc, crtc);
> > > > }
> > > > } else {
> > > > list_for_each_entry(enc, &dev->mode_config.encoder_list,
> > > > head) {
> > > > @@ -791,7 +789,7 @@ static void _dpu_crtc_vblank_enable_no_lock(
> > > > DRMID(enc), enable,
> > > > dpu_crtc);
> > > >
> > > > - dpu_encoder_register_vblank_callback(enc, NULL,
> > > > NULL);
> > > > + dpu_encoder_assign_crtc(enc, NULL);
> > > > }
> > > > }
> > > > }
> > > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
> > > > b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
> > > > index 93d21a61a040..54595cc29be5 100644
> > > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
> > > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
> > > > @@ -270,6 +270,12 @@ static inline int dpu_crtc_frame_pending(struct
> > > > drm_crtc *crtc)
> > > > */
> > > > int dpu_crtc_vblank(struct drm_crtc *crtc, bool en);
> > > >
> > > > +/**
> > > > + * dpu_crtc_vblank_callback - called on vblank irq, issues completion
> > > > events
> > > > + * @crtc: Pointer to drm crtc object
> > > > + */
> > > > +void dpu_crtc_vblank_callback(struct drm_crtc *crtc);
> > > > +
> > > > /**
> > > > * dpu_crtc_commit_kickoff - trigger kickoff of the commit for this
> > > > crtc
> > > > * @crtc: Pointer to drm crtc object
> > > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > > > b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > > > index d89ac520f7e6..fd6514f681ae 100644
> > > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > > > @@ -142,9 +142,11 @@ 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_vblank_cb: Callback into the upper layer / CRTC for
> > > > - * notification of the VBLANK
> > > > - * @crtc_vblank_cb_data: Data from upper layer for VBLANK
> > > > notification
> > > > + * @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.
> > > > * @crtc_kickoff_cb: Callback into CRTC that will flush
> > & start
> > > > * all CTL paths
> > > > * @crtc_kickoff_cb_data: Opaque user data given to crtc_kickoff_cb
> > > > @@ -186,8 +188,7 @@ struct dpu_encoder_virt {
> > > >
> > > > bool intfs_swapped;
> > > >
> > > > - void (*crtc_vblank_cb)(void *);
> > > > - void *crtc_vblank_cb_data;
> > > > + struct drm_crtc *crtc;
> > > >
> > > > struct dentry *debugfs_root;
> > > > struct mutex enc_lock;
> > > > @@ -1241,8 +1242,8 @@ static void dpu_encoder_vblank_callback(struct
> > > > drm_encoder *drm_enc,
> > > > dpu_enc = to_dpu_encoder_virt(drm_enc);
> > > >
> > > > spin_lock_irqsave(&dpu_enc->enc_spinlock, lock_flags);
> > > > - if (dpu_enc->crtc_vblank_cb)
> > > > - dpu_enc->crtc_vblank_cb(dpu_enc->crtc_vblank_cb_data);
> > > > + 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);
> > > > @@ -1262,15 +1263,14 @@ static void
> > dpu_encoder_underrun_callback(struct
> > > > drm_encoder *drm_enc,
> > > > DPU_ATRACE_END("encoder_underrun_callback");
> > > > }
> > > >
> > > > -void dpu_encoder_register_vblank_callback(struct drm_encoder
> > *drm_enc,
> > > > - void (*vbl_cb)(void *), void *vbl_data)
> > > > +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;
> > > > bool enable;
> > > > int i;
> > > >
> > > > - enable = vbl_cb ? true : false;
> > > > + enable = crtc ? true : false;
> > > >
> > > > if (!drm_enc) {
> > > > DPU_ERROR("invalid encoder\n");
> > > > @@ -1279,8 +1279,9 @@ void dpu_encoder_register_vblank_callback(struct
> > > > drm_encoder *drm_enc,
> > > > trace_dpu_enc_vblank_cb(DRMID(drm_enc), enable);
> > > >
> > > > spin_lock_irqsave(&dpu_enc->enc_spinlock, lock_flags);
> > > > - dpu_enc->crtc_vblank_cb = vbl_cb;
> > > > - dpu_enc->crtc_vblank_cb_data = vbl_data;
> > > > + /* 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);
> > > >
> > > > for (i = 0; i < dpu_enc->num_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 aa4f135218fa..be1d80867834 100644
> > > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> > > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> > > > @@ -55,14 +55,12 @@ void dpu_encoder_get_hw_resources(struct
> > drm_encoder
> > > > *encoder,
> > > > struct dpu_encoder_hw_resources
> > > > *hw_res);
> > > >
> > > > /**
> > > > - * dpu_encoder_register_vblank_callback - provide callback to encoder
> > > > that
> > > > - * will be called on the next vblank.
> > > > + * dpu_encoder_assign_crtc - Link the encoder to the crtc it's
> > assigned
> > > > to
> > > > * @encoder: encoder pointer
> > > > - * @cb: callback pointer, provide NULL to deregister and
> > > > disable IRQs
> > > > - * @data: user data provided to callback
> > > > + * @crtc: crtc pointer
> > > > */
> > > > -void dpu_encoder_register_vblank_callback(struct drm_encoder
> > *encoder,
> > > > - void (*cb)(void *), void *data);
> > > > +void dpu_encoder_assign_crtc(struct drm_encoder *encoder,
> > > > + struct drm_crtc *crtc);
> > > >
> > > > /**
> > > > * dpu_encoder_register_frame_event_callback - provide callback to
> > > > encoder that
> > >
> > > --
> > > Jeykumar S
>
> --
> Jeykumar S
--
Sean Paul, Software Engineer, Google / Chromium OS
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