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Message-ID: <Zx-4LsWPQEB_1mED@intel.com>
Date: Mon, 28 Oct 2024 18:13:34 +0200
From: Ville Syrjälä <ville.syrjala@...ux.intel.com>
To: linux@...blig.org
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
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.
The EXPORT_SYMBOL() looks completely pointless though.
>
> 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
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