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drm: Add get_scanout_position() to struct drm_crtc_helper_funcs

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The new callback get_scanout_position() reads the current location
of the scanout process. The operation is currently located in struct
drm_driver, but really belongs to the CRTC. Drivers will be converted
in separate patches.

To help with the conversion, the timestamp calculation has been
moved from drm_calc_vbltimestamp_from_scanoutpos() to
drm_crtc_vblank_helper_get_vblank_timestamp_internal(). The helper
function supports the new and old interface of get_scanout_position().
drm_calc_vbltimestamp_from_scanoutpos() remains as a wrapper around
the new function.

Callback functions return the scanout position from the CRTC. The
legacy version of the interface receives the device and pipe index,
the modern version receives a pointer to the CRTC. We keep the
legacy version until all drivers have been converted.

v4:
	* 80-character line fixes
v3:
	* refactor drm_calc_vbltimestamp_from_scanoutpos() to minimize
	  code duplication
	* define types for get_scanout_position() callbacks
v2:
	* fix logical op in drm_calc_vbltimestamp_from_scanoutpos()

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Yannick Fertré <yannick.fertre@st.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200123135943.24140-3-tzimmermann@suse.de
This commit is contained in:
Thomas Zimmermann
2020-01-23 14:59:23 +01:00
parent 9e0e8f01c8
commit f1e2b6371c
4 changed files with 157 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files

101
drivers/gpu/drm/drm_vblank.c
View File

@@ -30,6 +30,7 @@
#include <drm/drm_crtc.h>
#include <drm/drm_drv.h>
#include <drm/drm_framebuffer.h>
#include <drm/drm_modeset_helper_vtables.h>
#include <drm/drm_print.h>
#include <drm/drm_vblank.h>
@@ -605,7 +606,7 @@ EXPORT_SYMBOL(drm_calc_timestamping_constants);
* Implements calculation of exact vblank timestamps from given drm_display_mode
* timings and current video scanout position of a CRTC. This can be directly
* used as the &drm_driver.get_vblank_timestamp implementation of a kms driver
* if &drm_driver.get_scanout_position is implemented.
* if &drm_crtc_helper_funcs.get_scanout_position is implemented.
*
* The current implementation only handles standard video modes. For double scan
* and interlaced modes the driver is supposed to adjust the hardware mode
@@ -627,28 +628,85 @@ bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
ktime_t *vblank_time,
bool in_vblank_irq)
{
struct timespec64 ts_etime, ts_vblank_time;
ktime_t stime, etime;
bool vbl_status;
struct drm_crtc *crtc;
const struct drm_display_mode *mode;
struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
int vpos, hpos, i;
int delta_ns, duration_ns;
if (!drm_core_check_feature(dev, DRIVER_MODESET))
return false;
crtc = drm_crtc_from_index(dev, pipe);
if (!crtc)
return false;
if (pipe >= dev->num_crtcs || !crtc) {
return drm_crtc_vblank_helper_get_vblank_timestamp_internal(crtc,
max_error,
vblank_time,
in_vblank_irq,
crtc->helper_private->get_scanout_position,
dev->driver->get_scanout_position);
}
EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
/**
* drm_crtc_vblank_helper_get_vblank_timestamp_internal - precise vblank
* timestamp helper
* @dev: DRM device
* @pipe: index of CRTC whose vblank timestamp to retrieve
* @max_error: Desired maximum allowable error in timestamps (nanosecs)
* On return contains true maximum error of timestamp
* @vblank_time: Pointer to time which should receive the 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.
* @get_scanout_position:
* Callback function to retrieve the scanout position. See
* @struct drm_crtc_helper_funcs.get_scanout_position.
* @get_scanout_position_legacy:
* Callback function to retrieve the scanout position. See
* @struct drm_driver.get_scanout_position.
*
* Implements calculation of exact vblank timestamps from given drm_display_mode
* timings and current video scanout position of a CRTC.
*
* The current implementation only handles standard video modes. For double scan
* and interlaced modes the driver is supposed to adjust the hardware mode
* (taken from &drm_crtc_state.adjusted mode for atomic modeset drivers) to
* match the scanout position reported.
*
* Note that atomic drivers must call drm_calc_timestamping_constants() before
* enabling a CRTC. The atomic helpers already take care of that in
* drm_atomic_helper_update_legacy_modeset_state().
*
* Returns:
*
* Returns true on success, and false on failure, i.e. when no accurate
* timestamp could be acquired.
*/
bool
drm_crtc_vblank_helper_get_vblank_timestamp_internal(
struct drm_crtc *crtc, int *max_error, ktime_t *vblank_time,
bool in_vblank_irq,
drm_vblank_get_scanout_position_func get_scanout_position,
drm_vblank_get_scanout_position_legacy_func get_scanout_position_legacy)
{
struct drm_device *dev = crtc->dev;
unsigned int pipe = crtc->index;
struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
struct timespec64 ts_etime, ts_vblank_time;
ktime_t stime, etime;
bool vbl_status;
const struct drm_display_mode *mode;
int vpos, hpos, i;
int delta_ns, duration_ns;
if (pipe >= dev->num_crtcs) {
DRM_ERROR("Invalid crtc %u\n", pipe);
return false;
}
/* Scanout position query not supported? Should not happen. */
if (!dev->driver->get_scanout_position) {
DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
if (!get_scanout_position && !get_scanout_position_legacy) {
DRM_ERROR("Called from CRTC w/o get_scanout_position()!?\n");
return false;
}
@@ -663,7 +721,6 @@ bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
if (mode->crtc_clock == 0) {
DRM_DEBUG("crtc %u: Noop due to uninitialized mode.\n", pipe);
WARN_ON_ONCE(drm_drv_uses_atomic_modeset(dev));
return false;
}
@@ -679,11 +736,19 @@ bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
* Get vertical and horizontal scanout position vpos, hpos,
* and bounding timestamps stime, etime, pre/post query.
*/
vbl_status = dev->driver->get_scanout_position(dev, pipe,
in_vblank_irq,
&vpos, &hpos,
&stime, &etime,
mode);
if (get_scanout_position) {
vbl_status = get_scanout_position(crtc,
in_vblank_irq,
&vpos, &hpos,
&stime, &etime,
mode);
} else {
vbl_status = get_scanout_position_legacy(dev, pipe,
in_vblank_irq,
&vpos, &hpos,
&stime, &etime,
mode);
}
/* Return as no-op if scanout query unsupported or failed. */
if (!vbl_status) {
@@ -735,7 +800,7 @@ bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
return true;
}
EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
EXPORT_SYMBOL(drm_crtc_vblank_helper_get_vblank_timestamp_internal);
/**
* drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent