diff options
Diffstat (limited to 'drivers/gpu/drm/drm_client_modeset.c')
| -rw-r--r-- | drivers/gpu/drm/drm_client_modeset.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_client_modeset.c b/drivers/gpu/drm/drm_client_modeset.c index 9c2c3b0c8c47..fc4caf7da5fc 100644 --- a/drivers/gpu/drm/drm_client_modeset.c +++ b/drivers/gpu/drm/drm_client_modeset.c @@ -1293,6 +1293,50 @@ int drm_client_modeset_dpms(struct drm_client_dev *client, int mode) } EXPORT_SYMBOL(drm_client_modeset_dpms); +/** + * drm_client_modeset_wait_for_vblank() - Wait for the next VBLANK to occur + * @client: DRM client + * @crtc_index: The ndex of the CRTC to wait on + * + * Block the caller until the given CRTC has seen a VBLANK. Do nothing + * if the CRTC is disabled. If there's another DRM master present, fail + * with -EBUSY. + * + * Returns: + * 0 on success, or negative error code otherwise. + */ +int drm_client_modeset_wait_for_vblank(struct drm_client_dev *client, unsigned int crtc_index) +{ + struct drm_device *dev = client->dev; + struct drm_crtc *crtc; + int ret; + + /* + * Rate-limit update frequency to vblank. If there's a DRM master + * present, it could interfere while we're waiting for the vblank + * event. Don't wait in this case. + */ + if (!drm_master_internal_acquire(dev)) + return -EBUSY; + + crtc = client->modesets[crtc_index].crtc; + + /* + * Only wait for a vblank event if the CRTC is enabled, otherwise + * just don't do anything, not even report an error. + */ + ret = drm_crtc_vblank_get(crtc); + if (!ret) { + drm_crtc_wait_one_vblank(crtc); + drm_crtc_vblank_put(crtc); + } + + drm_master_internal_release(dev); + + return 0; +} +EXPORT_SYMBOL(drm_client_modeset_wait_for_vblank); + #ifdef CONFIG_DRM_KUNIT_TEST #include "tests/drm_client_modeset_test.c" #endif |