From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Subject: Re: [Intel-gfx] [PATCH v2 02/21] drm: Evaluate struct drm_device.vblank_disable_immediate on each use Date: Wed, 15 Jan 2020 16:37:57 +0200 Message-ID: <20200115143757.GZ13686@intel.com> References: <20200115121652.7050-1-tzimmermann@suse.de> <20200115121652.7050-3-tzimmermann@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: <20200115121652.7050-3-tzimmermann@suse.de> Sender: linux-arm-msm-owner@vger.kernel.org To: Thomas Zimmermann Cc: airlied@linux.ie, daniel@ffwll.ch, alexander.deucher@amd.com, christian.koenig@amd.com, David1.Zhou@amd.com, maarten.lankhorst@linux.intel.com, patrik.r.jakobsson@gmail.com, robdclark@gmail.com, sean@poorly.run, benjamin.gaignard@linaro.org, vincent.abriou@st.com, yannick.fertre@st.com, philippe.cornu@st.com, mcoquelin.stm32@gmail.com, alexandre.torgue@st.com, eric@anholt.net, rodrigosiqueiramelo@gmail.com, hamohammed.sa@gmail.com, linux-graphics-maintainer@vmware.com, thellstrom@vmware.com, bskeggs@redhat.com, harry.wentland@amd.com, sunpeng.li@amd.com, jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com, rodrigo.vivi@intel.com, linux-arm-msm@vger.kernel.org, intel-gfx@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, nouveau@lists.fre List-Id: nouveau.vger.kernel.org On Wed, Jan 15, 2020 at 01:16:33PM +0100, Thomas Zimmermann wrote: > VBLANK interrupts can be disabled immediately or with a delay, where the > latter is the default. The former option can be selected by setting > get_vblank_timestamp, and enabling vblank_disable_immediate in struct > drm_device. > > The setup is only evaluated once when DRM initializes VBLANKs. Evaluating > the settings on each use of vblank_disable_immediate will allow for easy > integration of CRTC VBLANK functions. > > Signed-off-by: Thomas Zimmermann > --- > drivers/gpu/drm/drm_vblank.c | 31 ++++++++++++++----------------- > 1 file changed, 14 insertions(+), 17 deletions(-) > > diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c > index 3f1dd54cc8bb..abb085c67d82 100644 > --- a/drivers/gpu/drm/drm_vblank.c > +++ b/drivers/gpu/drm/drm_vblank.c > @@ -481,19 +481,6 @@ int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs) > > DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n"); > > - /* Driver specific high-precision vblank timestamping supported? */ > - if (dev->driver->get_vblank_timestamp) > - DRM_INFO("Driver supports precise vblank timestamp query.\n"); > - else > - DRM_INFO("No driver support for vblank timestamp query.\n"); > - > - /* Must have precise timestamping for reliable vblank instant disable */ > - if (dev->vblank_disable_immediate && !dev->driver->get_vblank_timestamp) { > - dev->vblank_disable_immediate = false; > - DRM_INFO("Setting vblank_disable_immediate to false because " > - "get_vblank_timestamp == NULL\n"); > - } Which drivers are so broken they set vblank_disable_immediate to true without having the vfunc specified? IMO this code should just go away (or converted to a WARN). > - > return 0; > > err: > @@ -1070,6 +1057,15 @@ int drm_crtc_vblank_get(struct drm_crtc *crtc) > } > EXPORT_SYMBOL(drm_crtc_vblank_get); > > +static bool __vblank_disable_immediate(struct drm_device *dev, unsigned int pipe) > +{ > + if (!dev->vblank_disable_immediate) > + return false; > + if (!dev->driver->get_vblank_timestamp) > + return false; > + return true; > +} > + > static void drm_vblank_put(struct drm_device *dev, unsigned int pipe) > { > struct drm_vblank_crtc *vblank = &dev->vblank[pipe]; > @@ -1086,7 +1082,7 @@ static void drm_vblank_put(struct drm_device *dev, unsigned int pipe) > return; > else if (drm_vblank_offdelay < 0) > vblank_disable_fn(&vblank->disable_timer); > - else if (!dev->vblank_disable_immediate) > + else if (__vblank_disable_immediate(dev, pipe)) > mod_timer(&vblank->disable_timer, > jiffies + ((drm_vblank_offdelay * HZ)/1000)); > } > @@ -1663,7 +1659,7 @@ int drm_wait_vblank_ioctl(struct drm_device *dev, void *data, > /* If the counter is currently enabled and accurate, short-circuit > * queries to return the cached timestamp of the last vblank. > */ > - if (dev->vblank_disable_immediate && > + if (__vblank_disable_immediate(dev, pipe) && > drm_wait_vblank_is_query(vblwait) && > READ_ONCE(vblank->enabled)) { > drm_wait_vblank_reply(dev, pipe, &vblwait->reply); > @@ -1820,7 +1816,7 @@ bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe) > * been signaled. The disable has to be last (after > * drm_handle_vblank_events) so that the timestamp is always accurate. > */ > - disable_irq = (dev->vblank_disable_immediate && > + disable_irq = (__vblank_disable_immediate(dev, pipe) && > drm_vblank_offdelay > 0 && > !atomic_read(&vblank->refcount)); > > @@ -1893,7 +1889,8 @@ int drm_crtc_get_sequence_ioctl(struct drm_device *dev, void *data, > pipe = drm_crtc_index(crtc); > > vblank = &dev->vblank[pipe]; > - vblank_enabled = dev->vblank_disable_immediate && READ_ONCE(vblank->enabled); > + vblank_enabled = __vblank_disable_immediate(dev, pipe) && > + READ_ONCE(vblank->enabled); > > if (!vblank_enabled) { > ret = drm_crtc_vblank_get(crtc); > -- > 2.24.1 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Ville Syrjälä Intel