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path: root/drivers/gpu/drm/drm_crtc.c
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Diffstat (limited to 'drivers/gpu/drm/drm_crtc.c')
-rw-r--r--drivers/gpu/drm/drm_crtc.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 080c8d361f1f..bd3c8b243447 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -47,6 +47,29 @@
#include "drm_internal.h"
/**
+ * drm_crtc_from_index - find the registered CRTC at an index
+ * @dev: DRM device
+ * @idx: index of registered CRTC to find for
+ *
+ * Given a CRTC index, return the registered CRTC from DRM device's
+ * list of CRTCs with matching index. This is the inverse of drm_crtc_index().
+ * It's useful in the vblank callbacks (like &drm_driver.enable_vblank or
+ * &drm_driver.disable_vblank), since that still deals with indices instead
+ * of pointers to &struct drm_crtc."
+ */
+struct drm_crtc *drm_crtc_from_index(struct drm_device *dev, int idx)
+{
+ struct drm_crtc *crtc;
+
+ drm_for_each_crtc(crtc, dev)
+ if (idx == crtc->index)
+ return crtc;
+
+ return NULL;
+}
+EXPORT_SYMBOL(drm_crtc_from_index);
+
+/**
* drm_crtc_force_disable - Forcibly turn off a CRTC
* @crtc: CRTC to turn off
*