From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Thomas Zimmermann <tzimmermann@suse.de>
Cc: hamohammed.sa@gmail.com, airlied@linux.ie,
nouveau@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
amd-gfx@lists.freedesktop.org, alexandre.torgue@st.com,
thellstrom@vmware.com, sean@poorly.run,
linux-graphics-maintainer@vmware.com, bskeggs@redhat.com,
mcoquelin.stm32@gmail.com, sunpeng.li@amd.com,
linux-arm-msm@vger.kernel.org, intel-gfx@lists.freedesktop.org,
rodrigo.vivi@intel.com, vincent.abriou@st.com,
rodrigosiqueiramelo@gmail.com, philippe.cornu@st.com,
yannick.fertre@st.com, alexander.deucher@amd.com,
freedreno@lists.freedesktop.org, christian.koenig@amd.com
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 [thread overview]
Message-ID: <20200115143757.GZ13686@intel.com> (raw)
In-Reply-To: <20200115121652.7050-3-tzimmermann@suse.de>
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 <tzimmermann@suse.de>
> ---
> 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
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2020-01-15 14:38 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-15 12:16 [PATCH v2 00/21] drm: Clean up VBLANK callbacks in struct drm_driver Thomas Zimmermann
2020-01-15 12:16 ` [PATCH v2 01/21] drm: Add get_scanout_position() to struct drm_crtc_helper_funcs Thomas Zimmermann
2020-01-15 12:16 ` [PATCH v2 02/21] drm: Evaluate struct drm_device.vblank_disable_immediate on each use Thomas Zimmermann
2020-01-15 14:37 ` Ville Syrjälä [this message]
2020-01-16 8:03 ` [Intel-gfx] " Thomas Zimmermann
2020-01-15 12:16 ` [PATCH v2 03/21] drm: Add get_vblank_timestamp() to struct drm_crtc_funcs Thomas Zimmermann
2020-01-15 14:49 ` [Intel-gfx] " Ville Syrjälä
2020-01-16 8:44 ` Thomas Zimmermann
2020-01-16 11:21 ` Ville Syrjälä
2020-01-15 12:16 ` [PATCH v2 04/21] drm/amdgpu: Convert to struct drm_crtc_helper_funcs.get_scanout_position() Thomas Zimmermann
2020-01-15 12:16 ` [PATCH v2 05/21] drm/amdgpu: Convert to CRTC VBLANK callbacks Thomas Zimmermann
2020-01-15 12:16 ` [PATCH v2 06/21] drm/gma500: " Thomas Zimmermann
2020-01-15 12:16 ` [PATCH v2 07/21] drm/i915: " Thomas Zimmermann
2020-01-15 12:38 ` Jani Nikula
2020-01-15 15:11 ` Ville Syrjälä
2020-01-15 12:16 ` [PATCH v2 08/21] drm/nouveau: Convert to struct drm_crtc_helper_funcs.get_scanout_position() Thomas Zimmermann
2020-01-15 12:16 ` [PATCH v2 09/21] drm/nouveau: Convert to CRTC VBLANK callbacks Thomas Zimmermann
2020-01-15 12:16 ` [PATCH v2 10/21] drm/radeon: Convert to struct drm_crtc_helper_funcs.get_scanout_position() Thomas Zimmermann
2020-01-15 12:16 ` [PATCH v2 11/21] drm/radeon: Convert to CRTC VBLANK callbacks Thomas Zimmermann
2020-01-15 12:16 ` [PATCH v2 12/21] drm/msm: Convert to struct drm_crtc_helper_funcs.get_scanout_position() Thomas Zimmermann
2020-01-15 12:16 ` [PATCH v2 13/21] drm/msm: Convert to CRTC VBLANK callbacks Thomas Zimmermann
2020-01-15 12:16 ` [PATCH v2 14/21] drm/stm: Convert to struct drm_crtc_helper_funcs.get_scanout_position() Thomas Zimmermann
2020-01-15 12:16 ` [PATCH v2 15/21] drm/stm: Convert to CRTC VBLANK callbacks Thomas Zimmermann
2020-01-15 12:16 ` [PATCH v2 16/21] drm/sti: " Thomas Zimmermann
2020-01-15 12:16 ` [PATCH v2 17/21] drm/vc4: Convert to struct drm_crtc_helper_funcs.get_scanout_position() Thomas Zimmermann
2020-01-15 12:16 ` [PATCH v2 18/21] drm/vc4: Convert to CRTC VBLANK callbacks Thomas Zimmermann
2020-01-15 12:16 ` [PATCH v2 19/21] drm/vkms: " Thomas Zimmermann
2020-01-15 23:18 ` Rodrigo Siqueira
2020-01-17 13:22 ` Thomas Zimmermann
2020-01-15 12:16 ` [PATCH v2 20/21] drm/vmwgfx: " Thomas Zimmermann
2020-01-15 12:16 ` [PATCH v2 21/21] drm: Clean-up VBLANK-related callbacks in struct drm_driver Thomas Zimmermann
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