On Sun, Jan 22, 2017 at 02:09:02PM +0800, Shawn Guo wrote:
> From: Shawn Guo <shawn.guo@xxxxxxxxxx>
>
> The vblank is mostly CRTC specific and implemented as part of CRTC
> driver. Let's keep the vblank hooks struct drm_driver for legacy
> drivers, and add corresponding hooks in struct drm_crtc_funcs. These
> hooks take struct drm_crtc pointer as argument, and will be called by
> core vblank handling code for MODESET drivers.
>
> Signed-off-by: Shawn Guo <shawn.guo@xxxxxxxxxx>
Looks great. Just a few tiny nits below.
Cheers, Daniel
> ---
> drivers/gpu/drm/drm_irq.c | 53 +++++++++++++++++++++++++++++++++++++++++------
> include/drm/drm_crtc.h | 34 ++++++++++++++++++++++++++++++
> include/drm/drm_drv.h | 9 ++++++++
> 3 files changed, 90 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
> index 88c69e71102e..604a2acda9d6 100644
> --- a/drivers/gpu/drm/drm_irq.c
> +++ b/drivers/gpu/drm/drm_irq.c
> @@ -89,6 +89,19 @@ static void store_vblank(struct drm_device *dev, unsigned int pipe,
> write_sequnlock(&vblank->seqlock);
> }
>
> +static u32 __get_vblank_counter(struct drm_device *dev, unsigned int pipe)
> +{
> + if (drm_core_check_feature(dev, DRIVER_MODESET)) {
> + struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
> +
> + if (crtc->funcs->get_vblank_counter)
> + return crtc->funcs->get_vblank_counter(crtc);
> + }
> +
> + /* fallback for legacy drivers */
Bikeshed: I'd drop these comments, it's kinda obvious what's going on.
> + return dev->driver->get_vblank_counter(dev, pipe);
I think a great follow-up here would be to do
if (dev->driver->get_vblank_counter)
return dev->driver->get_vblank_counter(dev, pipe);
return drm_vblank_no_hw_counter(dev,pipe);
here (i.e. making get_vblank_counter optional), and then removing
drm_vblank_no_hw_counter from all drivers. We might even want to unexport
it, and adjust the help-text to state that hw without a vblank counter
should leave this hook as NULL.
> +}
> +
> /*
> * Reset the stored timestamp for the current vblank count to correspond
> * to the last vblank occurred.
> @@ -112,9 +125,9 @@ static void drm_reset_vblank_timestamp(struct drm_device *dev, unsigned int pipe
> * when drm_vblank_enable() applies the diff
> */
> do {
> - cur_vblank = dev->driver->get_vblank_counter(dev, pipe);
> + cur_vblank = __get_vblank_counter(dev, pipe);
> rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, 0);
> - } while (cur_vblank != dev->driver->get_vblank_counter(dev, pipe) && --count > 0);
> + } while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
>
> /*
> * Only reinitialize corresponding vblank timestamp if high-precision query
> @@ -168,9 +181,9 @@ static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe,
> * corresponding vblank timestamp.
> */
> do {
> - cur_vblank = dev->driver->get_vblank_counter(dev, pipe);
> + cur_vblank = __get_vblank_counter(dev, pipe);
> rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, flags);
> - } while (cur_vblank != dev->driver->get_vblank_counter(dev, pipe) && --count > 0);
> + } while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
>
> if (dev->max_vblank_count != 0) {
> /* trust the hw counter when it's around */
> @@ -275,6 +288,21 @@ u32 drm_accurate_vblank_count(struct drm_crtc *crtc)
> }
> EXPORT_SYMBOL(drm_accurate_vblank_count);
>
> +static void __disable_vblank(struct drm_device *dev, unsigned int pipe)
> +{
> + if (drm_core_check_feature(dev, DRIVER_MODESET)) {
> + struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
> +
> + if (crtc->funcs->disable_vblank) {
> + crtc->funcs->disable_vblank(crtc);
> + return;
> + }
> + }
> +
> + /* fallback for legacy drivers */
> + dev->driver->disable_vblank(dev, pipe);
> +}
> +
> /*
> * Disable vblank irq's on crtc, make sure that last vblank count
> * of hardware and corresponding consistent software vblank counter
> @@ -298,7 +326,7 @@ static void vblank_disable_and_save(struct drm_device *dev, unsigned int pipe)
> * hardware potentially runtime suspended.
> */
> if (vblank->enabled) {
> - dev->driver->disable_vblank(dev, pipe);
> + __disable_vblank(dev, pipe);
> vblank->enabled = false;
> }
>
> @@ -1054,6 +1082,19 @@ void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
> }
> EXPORT_SYMBOL(drm_crtc_send_vblank_event);
>
> +static int __enable_vblank(struct drm_device *dev, unsigned int pipe)
> +{
> + if (drm_core_check_feature(dev, DRIVER_MODESET)) {
> + struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
> +
> + if (crtc->funcs->enable_vblank)
> + return crtc->funcs->enable_vblank(crtc);
> + }
> +
> + /* fallback for legacy drivers */
> + return dev->driver->enable_vblank(dev, pipe);
> +}
> +
> /**
> * drm_vblank_enable - enable the vblank interrupt on a CRTC
> * @dev: DRM device
> @@ -1079,7 +1120,7 @@ static int drm_vblank_enable(struct drm_device *dev, unsigned int pipe)
> * timestamps. Filtercode in drm_handle_vblank() will
> * prevent double-accounting of same vblank interval.
> */
> - ret = dev->driver->enable_vblank(dev, pipe);
> + ret = __enable_vblank(dev, pipe);
> DRM_DEBUG("enabling vblank on crtc %u, ret: %d\n", pipe, ret);
> if (ret)
> atomic_dec(&vblank->refcount);
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index 06c943d1e04c..8b2f7266eada 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -600,6 +600,40 @@ struct drm_crtc_funcs {
> */
> void (*atomic_print_state)(struct drm_printer *p,
> const struct drm_crtc_state *state);
> +
> + /**
> + * @get_vblank_counter:
> + *
> + * Driver callback for fetching a raw hardware vblank counter for the
> + * CRTC. It's meant to be used by new drivers as the replacement of
> + * &drm_driver.get_vblank_counter hook.
Compared to the kerneldoc in drm_drv.h it misses the paragraph about
wrap-around handling. Also this is missing the note about what to do if
you don't have a vblank counter, but I think making the hook optional like
I suggested above would be even better. If you do decided to make the hook
optional, then please state that in the kernel-doc here too.
> + *
> + * Returns:
> + *
> + * Raw vblank counter value.
> + */
> + u32 (*get_vblank_counter)(struct drm_crtc *crtc);
> +
> + /**
> + * @enable_vblank:
> + *
> + * Enable vblank interrupts for the CRTC. It's meant to be used by
> + * new drivers as the replacement of &drm_driver.enable_vblank hook.
> + *
> + * Returns:
> + *
> + * Zero on success, appropriate errno if the vblank interrupt cannot
> + * be enabled.
> + */
> + int (*enable_vblank)(struct drm_crtc *crtc);
> +
> + /**
> + * @disable_vblank:
> + *
> + * Disable vblank interrupts for the CRTC. It's meant to be used by
> + * new drivers as the replacement of &drm_driver.disable_vblank hook.
> + */
> + void (*disable_vblank)(struct drm_crtc *crtc);
> };
>
> /**
> diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
> index 34ece393c639..6c325baddc40 100644
> --- a/include/drm/drm_drv.h
> +++ b/include/drm/drm_drv.h
> @@ -123,6 +123,9 @@ struct drm_driver {
> * drm_crtc_vblank_off() and drm_crtc_vblank_on() when disabling or
> * enabling a CRTC.
> *
> + * This is deprecated and should not be used by new drivers.
> + * Use &drm_crtc_funcs.get_vblank_counter instead.
> + *
> * Returns:
> *
> * Raw vblank counter value.
> @@ -135,6 +138,9 @@ struct drm_driver {
> * Enable vblank interrupts for the CRTC specified with the pipe
> * argument.
> *
> + * This is deprecated and should not be used by new drivers.
> + * Use &drm_crtc_funcs.enable_vblank instead.
> + *
> * Returns:
> *
> * Zero on success, appropriate errno if the given @crtc's vblank
> @@ -147,6 +153,9 @@ struct drm_driver {
> *
> * Disable vblank interrupts for the CRTC specified with the pipe
> * argument.
> + *
> + * This is deprecated and should not be used by new drivers.
> + * Use &drm_crtc_funcs.disable_vblank instead.
> */
> void (*disable_vblank) (struct drm_device *dev, unsigned int pipe);
>
> --
> 1.9.1
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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