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Message-ID: <Zx_Bzho9M3bGshLH@gallifrey>
Date: Mon, 28 Oct 2024 16:54:38 +0000
From: "Dr. David Alan Gilbert" <linux@...blig.org>
To: Ville Syrjälä <ville.syrjala@...ux.intel.com>
Cc: maarten.lankhorst@...ux.intel.com, mripard@...nel.org,
tzimmermann@...e.de, airlied@...il.com, simona@...ll.ch,
dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/5] drm/vblank: Remove unused
drm_crtc_vblank_count_and_time
* Ville Syrjälä (ville.syrjala@...ux.intel.com) wrote:
> On Wed, Oct 23, 2024 at 12:29:32AM +0100, linux@...blig.org wrote:
> > From: "Dr. David Alan Gilbert" <linux@...blig.org>
> >
> > drm_crtc_vblank_count_and_time() was explicitly added by
> > commit cf6483050e9b ("drm/irq: Add drm_crtc_vblank_count_and_time()")
> > in 2015, but never used.
>
> I see a bunch of places that could trivially use it.
> That might be the more sensible thing to do so that
> we keep moving towards using the crtc for everything.
Do you intend to send those since you understand it?
> The EXPORT_SYMBOL() looks completely pointless though.
Hmm, we probably shouldn't change that until something uses it?
Dave
> >
> > Remove it, and rework comments that reference it.
> >
> > Signed-off-by: Dr. David Alan Gilbert <linux@...blig.org>
> > ---
> > drivers/gpu/drm/drm_vblank.c | 44 +++++++-----------------------------
> > include/drm/drm_vblank.h | 10 ++++----
> > 2 files changed, 12 insertions(+), 42 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
> > index 94e45ed6869d..67d6367e9f4b 100644
> > --- a/drivers/gpu/drm/drm_vblank.c
> > +++ b/drivers/gpu/drm/drm_vblank.c
> > @@ -908,10 +908,10 @@ drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe,
> > * drm_crtc_accurate_vblank_count() for such use-cases.
> > *
> > * Note that for a given vblank counter value drm_crtc_handle_vblank()
> > - * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
> > - * provide a barrier: Any writes done before calling
> > - * drm_crtc_handle_vblank() will be visible to callers of the later
> > - * functions, if the vblank count is the same or a later one.
> > + * and drm_crtc_vblank_count() provide a barrier:
> > + * Any writes done before calling drm_crtc_handle_vblank() will be
> > + * visible to callers of the later functions, if the vblank count is
> > + * the same or a later one.
> > *
> > * See also &drm_vblank_crtc.count.
> > *
> > @@ -936,7 +936,6 @@ EXPORT_SYMBOL(drm_crtc_vblank_count);
> > * modesetting activity. Returns corresponding system timestamp of the time
> > * of the vblank interval that corresponds to the current vblank counter value.
> > *
> > - * This is the legacy version of drm_crtc_vblank_count_and_time().
> > */
> > static u64 drm_vblank_count_and_time(struct drm_device *dev, unsigned int pipe,
> > ktime_t *vblanktime)
> > @@ -959,33 +958,6 @@ static u64 drm_vblank_count_and_time(struct drm_device *dev, unsigned int pipe,
> > return vblank_count;
> > }
> >
> > -/**
> > - * drm_crtc_vblank_count_and_time - retrieve "cooked" vblank counter value
> > - * and the system timestamp corresponding to that vblank counter value
> > - * @crtc: which counter to retrieve
> > - * @vblanktime: Pointer to time to receive the vblank timestamp.
> > - *
> > - * Fetches the "cooked" vblank count value that represents the number of
> > - * vblank events since the system was booted, including lost events due to
> > - * modesetting activity. Returns corresponding system timestamp of the time
> > - * of the vblank interval that corresponds to the current vblank counter value.
> > - *
> > - * Note that for a given vblank counter value drm_crtc_handle_vblank()
> > - * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
> > - * provide a barrier: Any writes done before calling
> > - * drm_crtc_handle_vblank() will be visible to callers of the later
> > - * functions, if the vblank count is the same or a later one.
> > - *
> > - * See also &drm_vblank_crtc.count.
> > - */
> > -u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
> > - ktime_t *vblanktime)
> > -{
> > - return drm_vblank_count_and_time(crtc->dev, drm_crtc_index(crtc),
> > - vblanktime);
> > -}
> > -EXPORT_SYMBOL(drm_crtc_vblank_count_and_time);
> > -
> > /**
> > * drm_crtc_next_vblank_start - calculate the time of the next vblank
> > * @crtc: the crtc for which to calculate next vblank time
> > @@ -1978,10 +1950,10 @@ EXPORT_SYMBOL(drm_handle_vblank);
> > * This is the native KMS version of drm_handle_vblank().
> > *
> > * Note that for a given vblank counter value drm_crtc_handle_vblank()
> > - * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
> > - * provide a barrier: Any writes done before calling
> > - * drm_crtc_handle_vblank() will be visible to callers of the later
> > - * functions, if the vblank count is the same or a later one.
> > + * and drm_crtc_vblank_count() * provide a barrier:
> > + * Any writes done before calling * drm_crtc_handle_vblank() will be
> > + * visible to callers of the later functions, if the vblank count is
> > + * the same or a later one.
> > *
> > * See also &drm_vblank_crtc.count.
> > *
> > diff --git a/include/drm/drm_vblank.h b/include/drm/drm_vblank.h
> > index 151ab1e85b1b..572e54425970 100644
> > --- a/include/drm/drm_vblank.h
> > +++ b/include/drm/drm_vblank.h
> > @@ -141,10 +141,10 @@ struct drm_vblank_crtc {
> > * Current software vblank counter.
> > *
> > * Note that for a given vblank counter value drm_crtc_handle_vblank()
> > - * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
> > - * provide a barrier: Any writes done before calling
> > - * drm_crtc_handle_vblank() will be visible to callers of the later
> > - * functions, iff the vblank count is the same or a later one.
> > + * and drm_crtc_vblank_count() provide a barrier:
> > + * Any writes done before calling drm_crtc_handle_vblank() will be
> > + * visible to callers of the later functions, iff the vblank count is
> > + * the same or a later one.
> > *
> > * IMPORTANT: This guarantee requires barriers, therefor never access
> > * this field directly. Use drm_crtc_vblank_count() instead.
> > @@ -260,8 +260,6 @@ struct drm_vblank_crtc *drm_crtc_vblank_crtc(struct drm_crtc *crtc);
> > int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
> > bool drm_dev_has_vblank(const struct drm_device *dev);
> > u64 drm_crtc_vblank_count(struct drm_crtc *crtc);
> > -u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
> > - ktime_t *vblanktime);
> > int drm_crtc_next_vblank_start(struct drm_crtc *crtc, ktime_t *vblanktime);
> > void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
> > struct drm_pending_vblank_event *e);
> > --
> > 2.47.0
>
> --
> Ville Syrjälä
> Intel
>
--
-----Open up your eyes, open up your mind, open up your code -------
/ Dr. David Alan Gilbert | Running GNU/Linux | Happy \
\ dave @ treblig.org | | In Hex /
\ _________________________|_____ http://www.treblig.org |_______/
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