| Message ID | 1459778134-30693-1-git-send-email-tomeu.vizoso@collabora.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Tomeu, On 4 April 2016 at 14:55, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote: > diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c > index 3b8f652698f8..8305bbd2a4d7 100644 > --- a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c > +++ b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c > @@ -280,7 +280,18 @@ int rockchip_drm_atomic_commit(struct drm_device *dev, > { > struct rockchip_drm_private *private = dev->dev_private; > struct rockchip_atomic_commit *commit = &private->commit; > - int ret; > + struct drm_crtc_state *crtc_state; > + struct drm_crtc *crtc; > + int i, ret; > + > + if (async) { > + for_each_crtc_in_state(state, crtc, crtc_state, i) { > + if (crtc->state->event || > + rockchip_drm_crtc_has_pending_event(crtc)) { > + return -EBUSY; > + } > + } > + } Hmmm ... Doesn't this trigger before the VOP atomic_begin() helper, meaning that anything with an event set will trigger the check? Seems like it should be && rather than ||. Also, I know rockchip_drm_vop.c isn't holding dev->event_lock when it checks vop->event, but it really should be ... and so should this check. Otherwise you can race with the IRQ handler, which isn't required to hold the CRTC lock. Cheers, Daniel
On 4 April 2016 at 17:44, Daniel Stone <daniel@fooishbar.org> wrote: > Hi Tomeu, > > On 4 April 2016 at 14:55, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote: >> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c >> index 3b8f652698f8..8305bbd2a4d7 100644 >> --- a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c >> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c >> @@ -280,7 +280,18 @@ int rockchip_drm_atomic_commit(struct drm_device *dev, >> { >> struct rockchip_drm_private *private = dev->dev_private; >> struct rockchip_atomic_commit *commit = &private->commit; >> - int ret; >> + struct drm_crtc_state *crtc_state; >> + struct drm_crtc *crtc; >> + int i, ret; >> + >> + if (async) { >> + for_each_crtc_in_state(state, crtc, crtc_state, i) { >> + if (crtc->state->event || >> + rockchip_drm_crtc_has_pending_event(crtc)) { >> + return -EBUSY; >> + } >> + } >> + } > > Hmmm ... > > Doesn't this trigger before the VOP atomic_begin() helper, meaning > that anything with an event set will trigger the check? Seems like it > should be && rather than ||. So, these are the two cases that this code aims to handle: 1. A previous request with an event set hasn't progressed to atomic_begin yet, so the event field in drm_crtc_state (at this point, the old state) is still populated but vop->event still isn't. 2. A previous request has already progressed to atomic_begin but we haven't gotten yet the interrupt that signals its completion, so vop->event is populated but crtc->state->event isn't anymore. My understanding is that in both cases there's a pending flip event and we have to return -EBUSY if it's as async request. > Also, I know rockchip_drm_vop.c isn't holding dev->event_lock when it > checks vop->event, but it really should be ... and so should this > check. Otherwise you can race with the IRQ handler, which isn't > required to hold the CRTC lock. Cool, thanks. Tomeu > Cheers, > Daniel > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel
Hi Tomeu, On 5 April 2016 at 16:07, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote: > On 4 April 2016 at 17:44, Daniel Stone <daniel@fooishbar.org> wrote: >> On 4 April 2016 at 14:55, Tomeu Vizoso <tomeu.vizoso@collabora.com> wrote: >>> + if (async) { >>> + for_each_crtc_in_state(state, crtc, crtc_state, i) { >>> + if (crtc->state->event || >>> + rockchip_drm_crtc_has_pending_event(crtc)) { >>> + return -EBUSY; >>> + } >>> + } >>> + } >> >> Hmmm ... >> >> Doesn't this trigger before the VOP atomic_begin() helper, meaning >> that anything with an event set will trigger the check? Seems like it >> should be && rather than ||. > > So, these are the two cases that this code aims to handle: > > 1. A previous request with an event set hasn't progressed to > atomic_begin yet, so the event field in drm_crtc_state (at this point, > the old state) is still populated but vop->event still isn't. Ah right, this was what I was missing: the async (non-blocking) implementation. Sounds good to me then. Cheers, Daniel
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_drv.h b/drivers/gpu/drm/rockchip/rockchip_drm_drv.h index 3529f692edb8..37952eefd33d 100644 --- a/drivers/gpu/drm/rockchip/rockchip_drm_drv.h +++ b/drivers/gpu/drm/rockchip/rockchip_drm_drv.h @@ -69,6 +69,7 @@ int rockchip_register_crtc_funcs(struct drm_crtc *crtc, void rockchip_unregister_crtc_funcs(struct drm_crtc *crtc); int rockchip_drm_crtc_mode_config(struct drm_crtc *crtc, int connector_type, int out_mode); +bool rockchip_drm_crtc_has_pending_event(struct drm_crtc *crtc); int rockchip_drm_dma_attach_device(struct drm_device *drm_dev, struct device *dev); void rockchip_drm_dma_detach_device(struct drm_device *drm_dev, diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c index 3b8f652698f8..8305bbd2a4d7 100644 --- a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c +++ b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c @@ -280,7 +280,18 @@ int rockchip_drm_atomic_commit(struct drm_device *dev, { struct rockchip_drm_private *private = dev->dev_private; struct rockchip_atomic_commit *commit = &private->commit; - int ret; + struct drm_crtc_state *crtc_state; + struct drm_crtc *crtc; + int i, ret; + + if (async) { + for_each_crtc_in_state(state, crtc, crtc_state, i) { + if (crtc->state->event || + rockchip_drm_crtc_has_pending_event(crtc)) { + return -EBUSY; + } + } + } ret = drm_atomic_helper_prepare_planes(dev, state); if (ret) diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c index e2118e62345b..5bcdd8dc7499 100644 --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c @@ -848,6 +848,11 @@ int rockchip_drm_crtc_mode_config(struct drm_crtc *crtc, } EXPORT_SYMBOL_GPL(rockchip_drm_crtc_mode_config); +bool rockchip_drm_crtc_has_pending_event(struct drm_crtc *crtc) +{ + return to_vop(crtc)->event; +} + static int vop_crtc_enable_vblank(struct drm_crtc *crtc) { struct vop *vop = to_vop(crtc);
As per the docs, atomic_commit should return -EBUSY "if an asycnhronous updated is requested and there is an earlier updated pending". v2: Use the status of the workqueue instead of vop->event, and don't add a superfluous wait on the workqueue. v3: Drop work_busy, as there's a sizeable delay when the worker finishes, which introduces a race in which the client has already received the last flip event but the next page flip ioctl will still return -EBUSY because work_busy returns outdated information. Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com> --- drivers/gpu/drm/rockchip/rockchip_drm_drv.h | 1 + drivers/gpu/drm/rockchip/rockchip_drm_fb.c | 13 ++++++++++++- drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 5 +++++ 3 files changed, 18 insertions(+), 1 deletion(-)