| Message ID | bbd6cfc198254a60d7369c0101ab027bb7b56946.1488592678.git-series.kieran.bingham+renesas@ideasonboard.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Geert Uytterhoeven |
| Headers | show |
Hi Kieran, Thank you for the patch. On Saturday 04 Mar 2017 02:01:19 Kieran Bingham wrote: > Currently we process page flip events on every display interrupt, > however this does not take into consideration the processing time needed > by the VSP1 utilised in the pipeline. > > Register a callback with the VSP driver to obtain completion events, and > track them so that we only perform page flips when the full display > pipeline has completed for the frame. > > Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com> > > --- > v2: > - Commit message completely re-worded for patch re-work. > - drm_crtc_handle_vblank() re-instated in event of rcrtc->pending > - removed passing of unnecessary 'data' through callbacks > - perform page flips from the VSP completion handler > - add locking around pending flags > > drivers/gpu/drm/rcar-du/rcar_du_crtc.c | 10 +++++++-- > drivers/gpu/drm/rcar-du/rcar_du_crtc.h | 2 ++- > drivers/gpu/drm/rcar-du/rcar_du_vsp.c | 29 +++++++++++++++++++++++++++- > 3 files changed, 39 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c > b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c index 7391dd95c733..b7ff00bb45de > 100644 > --- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c > +++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c > @@ -299,7 +299,7 @@ static void rcar_du_crtc_update_planes(struct > rcar_du_crtc *rcrtc) * Page Flip > */ > > -static void rcar_du_crtc_finish_page_flip(struct rcar_du_crtc *rcrtc) > +void rcar_du_crtc_finish_page_flip(struct rcar_du_crtc *rcrtc) > { > struct drm_pending_vblank_event *event; > struct drm_device *dev = rcrtc->crtc.dev; > @@ -328,7 +328,7 @@ static bool rcar_du_crtc_page_flip_pending(struct > rcar_du_crtc *rcrtc) bool pending; > > spin_lock_irqsave(&dev->event_lock, flags); > - pending = rcrtc->event != NULL; > + pending = (rcrtc->event != NULL) || (rcrtc->pending); No need for parenthesis. > spin_unlock_irqrestore(&dev->event_lock, flags); > > return pending; > @@ -579,6 +579,12 @@ static irqreturn_t rcar_du_crtc_irq(int irq, void *arg) > > if (status & DSSR_FRM) { > drm_crtc_handle_vblank(&rcrtc->crtc); > + > + if (rcrtc->pending) { > + trace_printk("VBlank loss due to VSP Overrun\n"); > + return IRQ_HANDLED; > + } > + More than that, now that the VSP completion handler finishes the page flip, you should skip the rcar_du_crtc_finish_page_flip() call here unconditionally on Gen3. Something like struct rcar_du_crtc *rcrtc = arg; struct rcar_du_device *rcdu = rcrtc->group->dev; ... if (status & DSSR_FRM) { drm_crtc_handle_vblank(&rcrtc->crtc); if (rcdu->info->gen < 3) rcar_du_crtc_finish_page_flip(rcrtc); ret = IRQ_HANDLED; } > rcar_du_crtc_finish_page_flip(rcrtc); > ret = IRQ_HANDLED; > } > diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.h > b/drivers/gpu/drm/rcar-du/rcar_du_crtc.h index a7194812997e..b73ec6de7af4 > 100644 > --- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.h > +++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.h > @@ -47,6 +47,7 @@ struct rcar_du_crtc { > > struct drm_pending_vblank_event *event; > wait_queue_head_t flip_wait; > + bool pending; > > unsigned int outputs; > > @@ -71,5 +72,6 @@ void rcar_du_crtc_resume(struct rcar_du_crtc *rcrtc); > > void rcar_du_crtc_route_output(struct drm_crtc *crtc, > enum rcar_du_output output); > +void rcar_du_crtc_finish_page_flip(struct rcar_du_crtc *rcrtc); > > #endif /* __RCAR_DU_CRTC_H__ */ > diff --git a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c > b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c index b0ff304ce3dc..1fcd311badb1 > 100644 > --- a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c > +++ b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c > @@ -28,6 +28,22 @@ > #include "rcar_du_kms.h" > #include "rcar_du_vsp.h" > > +static void rcar_du_vsp_complete(void *private) > +{ > + struct rcar_du_crtc *crtc = (struct rcar_du_crtc *)private; > + struct drm_device *dev = crtc->crtc.dev; > + unsigned long flags; > + bool pending; > + > + spin_lock_irqsave(&dev->event_lock, flags); > + pending = crtc->pending; > + crtc->pending = false; > + spin_unlock_irqrestore(&dev->event_lock, flags); > + > + if (pending) > + rcar_du_crtc_finish_page_flip(crtc); This seems to duplicate the synchronization mechanism based on events in rcar_du_crtc_atomic_begin(). I need to check that in more details. > +} > + > void rcar_du_vsp_enable(struct rcar_du_crtc *crtc) > { > const struct drm_display_mode *mode = &crtc->crtc.state- >adjusted_mode; > @@ -35,6 +51,8 @@ void rcar_du_vsp_enable(struct rcar_du_crtc *crtc) > struct vsp1_du_lif_config cfg = { > .width = mode->hdisplay, > .height = mode->vdisplay, > + .callback = rcar_du_vsp_complete, > + .callback_data = crtc, > }; > struct rcar_du_plane_state state = { > .state = { > @@ -85,6 +103,17 @@ void rcar_du_vsp_atomic_begin(struct rcar_du_crtc *crtc) > > void rcar_du_vsp_atomic_flush(struct rcar_du_crtc *crtc) > { > + struct drm_device *dev = crtc->crtc.dev; > + unsigned long flags; > + bool pending; > + > + spin_lock_irqsave(&dev->event_lock, flags); > + pending = crtc->pending; > + crtc->pending = true; > + spin_unlock_irqrestore(&dev->event_lock, flags); > + > + WARN_ON(pending); > + > vsp1_du_atomic_flush(crtc->vsp->vsp); > }
Hi Kieran, On Saturday 04 Mar 2017 15:07:09 Laurent Pinchart wrote: > On Saturday 04 Mar 2017 02:01:19 Kieran Bingham wrote: > > Currently we process page flip events on every display interrupt, > > however this does not take into consideration the processing time needed > > by the VSP1 utilised in the pipeline. > > > > Register a callback with the VSP driver to obtain completion events, and > > track them so that we only perform page flips when the full display > > pipeline has completed for the frame. > > > > Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com> > > > > --- > > > > v2: > > - Commit message completely re-worded for patch re-work. > > - drm_crtc_handle_vblank() re-instated in event of rcrtc->pending > > - removed passing of unnecessary 'data' through callbacks > > - perform page flips from the VSP completion handler > > - add locking around pending flags > > > > drivers/gpu/drm/rcar-du/rcar_du_crtc.c | 10 +++++++-- > > drivers/gpu/drm/rcar-du/rcar_du_crtc.h | 2 ++- > > drivers/gpu/drm/rcar-du/rcar_du_vsp.c | 29 +++++++++++++++++++++++++++- > > 3 files changed, 39 insertions(+), 2 deletions(-) [snip] > > diff --git a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c > > b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c index b0ff304ce3dc..1fcd311badb1 > > 100644 > > --- a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c > > +++ b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c [snip] > > @@ -28,6 +28,22 @@ > > #include "rcar_du_kms.h" > > #include "rcar_du_vsp.h" > > > > +static void rcar_du_vsp_complete(void *private) > > +{ > > + struct rcar_du_crtc *crtc = (struct rcar_du_crtc *)private; > > + struct drm_device *dev = crtc->crtc.dev; > > + unsigned long flags; > > + bool pending; > > + > > + spin_lock_irqsave(&dev->event_lock, flags); > > + pending = crtc->pending; > > + crtc->pending = false; > > + spin_unlock_irqrestore(&dev->event_lock, flags); > > + > > + if (pending) > > + rcar_du_crtc_finish_page_flip(crtc); > > This seems to duplicate the synchronization mechanism based on events in > rcar_du_crtc_atomic_begin(). I need to check that in more details. Indeed it does, and I don't think that's needed. You might be able to shorten the race window on the DU side, but you won't be able to close it completely as detecting the race requires information that is only available to the VSP driver. Fixing the race on the VSP side will make this dead code, so you can remove the addition of the pending flag from this patch. > > +}
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c index 7391dd95c733..b7ff00bb45de 100644 --- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c +++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c @@ -299,7 +299,7 @@ static void rcar_du_crtc_update_planes(struct rcar_du_crtc *rcrtc) * Page Flip */ -static void rcar_du_crtc_finish_page_flip(struct rcar_du_crtc *rcrtc) +void rcar_du_crtc_finish_page_flip(struct rcar_du_crtc *rcrtc) { struct drm_pending_vblank_event *event; struct drm_device *dev = rcrtc->crtc.dev; @@ -328,7 +328,7 @@ static bool rcar_du_crtc_page_flip_pending(struct rcar_du_crtc *rcrtc) bool pending; spin_lock_irqsave(&dev->event_lock, flags); - pending = rcrtc->event != NULL; + pending = (rcrtc->event != NULL) || (rcrtc->pending); spin_unlock_irqrestore(&dev->event_lock, flags); return pending; @@ -579,6 +579,12 @@ static irqreturn_t rcar_du_crtc_irq(int irq, void *arg) if (status & DSSR_FRM) { drm_crtc_handle_vblank(&rcrtc->crtc); + + if (rcrtc->pending) { + trace_printk("VBlank loss due to VSP Overrun\n"); + return IRQ_HANDLED; + } + rcar_du_crtc_finish_page_flip(rcrtc); ret = IRQ_HANDLED; } diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.h b/drivers/gpu/drm/rcar-du/rcar_du_crtc.h index a7194812997e..b73ec6de7af4 100644 --- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.h +++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.h @@ -47,6 +47,7 @@ struct rcar_du_crtc { struct drm_pending_vblank_event *event; wait_queue_head_t flip_wait; + bool pending; unsigned int outputs; @@ -71,5 +72,6 @@ void rcar_du_crtc_resume(struct rcar_du_crtc *rcrtc); void rcar_du_crtc_route_output(struct drm_crtc *crtc, enum rcar_du_output output); +void rcar_du_crtc_finish_page_flip(struct rcar_du_crtc *rcrtc); #endif /* __RCAR_DU_CRTC_H__ */ diff --git a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c index b0ff304ce3dc..1fcd311badb1 100644 --- a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c +++ b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c @@ -28,6 +28,22 @@ #include "rcar_du_kms.h" #include "rcar_du_vsp.h" +static void rcar_du_vsp_complete(void *private) +{ + struct rcar_du_crtc *crtc = (struct rcar_du_crtc *)private; + struct drm_device *dev = crtc->crtc.dev; + unsigned long flags; + bool pending; + + spin_lock_irqsave(&dev->event_lock, flags); + pending = crtc->pending; + crtc->pending = false; + spin_unlock_irqrestore(&dev->event_lock, flags); + + if (pending) + rcar_du_crtc_finish_page_flip(crtc); +} + void rcar_du_vsp_enable(struct rcar_du_crtc *crtc) { const struct drm_display_mode *mode = &crtc->crtc.state->adjusted_mode; @@ -35,6 +51,8 @@ void rcar_du_vsp_enable(struct rcar_du_crtc *crtc) struct vsp1_du_lif_config cfg = { .width = mode->hdisplay, .height = mode->vdisplay, + .callback = rcar_du_vsp_complete, + .callback_data = crtc, }; struct rcar_du_plane_state state = { .state = { @@ -85,6 +103,17 @@ void rcar_du_vsp_atomic_begin(struct rcar_du_crtc *crtc) void rcar_du_vsp_atomic_flush(struct rcar_du_crtc *crtc) { + struct drm_device *dev = crtc->crtc.dev; + unsigned long flags; + bool pending; + + spin_lock_irqsave(&dev->event_lock, flags); + pending = crtc->pending; + crtc->pending = true; + spin_unlock_irqrestore(&dev->event_lock, flags); + + WARN_ON(pending); + vsp1_du_atomic_flush(crtc->vsp->vsp); }
Currently we process page flip events on every display interrupt, however this does not take into consideration the processing time needed by the VSP1 utilised in the pipeline. Register a callback with the VSP driver to obtain completion events, and track them so that we only perform page flips when the full display pipeline has completed for the frame. Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com> --- v2: - Commit message completely re-worded for patch re-work. - drm_crtc_handle_vblank() re-instated in event of rcrtc->pending - removed passing of unnecessary 'data' through callbacks - perform page flips from the VSP completion handler - add locking around pending flags drivers/gpu/drm/rcar-du/rcar_du_crtc.c | 10 +++++++-- drivers/gpu/drm/rcar-du/rcar_du_crtc.h | 2 ++- drivers/gpu/drm/rcar-du/rcar_du_vsp.c | 29 +++++++++++++++++++++++++++- 3 files changed, 39 insertions(+), 2 deletions(-)