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drm: Add get_vblank_timestamp() to struct drm_crtc_funcs

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The callback get_vblank_timestamp() is currently located in struct
drm_driver, but really belongs into struct drm_crtc_funcs. Add an
equivalent there. Driver will be converted in separate patches.

The default implementation is drm_calc_vbltimestamp_from_scanoutpos().
The patch adds drm_crtc_vblank_helper_get_vblank_timestamp(), which is
an implementation for the CRTC callback.

v4:
	* more readable code for setting high_prec (Ville, Jani)
v3:
	* use refactored timestamp calculation to minimize duplicated code
	* do more checks for crtc != NULL to support legacy drivers
v2:
	* rename helper to drm_crtc_vblank_helper_get_vblank_timestamp()
	* replace drm_calc_vbltimestamp_from_scanoutpos() with
	  drm_crtc_vblank_helper_get_vblank_timestamp() in docs

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200123135943.24140-4-tzimmermann@suse.de
This commit is contained in:
Thomas Zimmermann
2020-01-23 14:59:24 +01:00
parent f1e2b6371c
commit 7fe3f0d15a
4 changed files with 125 additions and 17 deletions
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46
include/drm/drm_crtc.h
View File

@@ -887,6 +887,47 @@ struct drm_crtc_funcs {
* new drivers as the replacement of &drm_driver.disable_vblank hook.
*/
void (*disable_vblank)(struct drm_crtc *crtc);
/**
* @get_vblank_timestamp:
*
* Called by drm_get_last_vbltimestamp(). Should return a precise
* timestamp when the most recent vblank interval ended or will end.
*
* Specifically, the timestamp in @vblank_time should correspond as
* closely as possible to the time when the first video scanline of
* the video frame after the end of vblank will start scanning out,
* the time immediately after end of the vblank interval. If the
* @crtc is currently inside vblank, this will be a time in the future.
* If the @crtc is currently scanning out a frame, this will be the
* past start time of the current scanout. This is meant to adhere
* to the OpenML OML_sync_control extension specification.
*
* Parameters:
*
* crtc:
* CRTC for which timestamp should be returned.
* max_error:
* Maximum allowable timestamp error in nanoseconds.
* Implementation should strive to provide timestamp
* with an error of at most max_error nanoseconds.
* Returns true upper bound on error for timestamp.
* vblank_time:
* Target location for returned vblank timestamp.
* in_vblank_irq:
* True when called from drm_crtc_handle_vblank(). Some drivers
* need to apply some workarounds for gpu-specific vblank irq quirks
* if flag is set.
*
* Returns:
*
* True on success, false on failure, which means the core should
* fallback to a simple timestamp taken in drm_crtc_handle_vblank().
*/
bool (*get_vblank_timestamp)(struct drm_crtc *crtc,
int *max_error,
ktime_t *vblank_time,
bool in_vblank_irq);
};
/**
@@ -994,11 +1035,12 @@ struct drm_crtc {
* Programmed mode in hw, after adjustments for encoders, crtc, panel
* scaling etc. Should only be used by legacy drivers, for high
* precision vblank timestamps in
* drm_calc_vbltimestamp_from_scanoutpos().
* drm_crtc_vblank_helper_get_vblank_timestamp().
*
* Note that atomic drivers should not use this, but instead use
* &drm_crtc_state.adjusted_mode. And for high-precision timestamps
* drm_calc_vbltimestamp_from_scanoutpos() used &drm_vblank_crtc.hwmode,
* drm_crtc_vblank_helper_get_vblank_timestamp() used
* &drm_vblank_crtc.hwmode,
* which is filled out by calling drm_calc_timestamping_constants().
*/
struct drm_display_mode hwmode;