drm/radeon: Add function for display scanout position query.

radeon_get_crtc_scanoutpos() returns the current horizontal
and vertical scanout position of a crtc. It also reports if
the display scanout is currently inside the vblank area.

hpos reports current horizontal pixel scanout position.
vpos reports the current scanned out line as a value >= 0
in active scanout. If the scanout is inside vblank area, it
reports a negative value, the number of scanlines until
end of vblank aka start of active scanout, e.g., -3 ==
"At most 3 scanlines until end of vblank".

This code is derived from radeon_pm_in_vbl(), tested on
R500 and R600.

Signed-off-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_mode.h b/drivers/gpu/drm/radeon/radeon_mode.h
index d25cf093c84..f4396d71b41 100644
--- a/drivers/gpu/drm/radeon/radeon_mode.h
+++ b/drivers/gpu/drm/radeon/radeon_mode.h
@@ -428,6 +428,11 @@ struct radeon_framebuffer {
 	struct drm_gem_object *obj;
 };
 
+/* radeon_get_crtc_scanoutpos() return flags */
+#define RADEON_SCANOUTPOS_VALID        (1 << 0)
+#define RADEON_SCANOUTPOS_INVBL        (1 << 1)
+#define RADEON_SCANOUTPOS_ACCURATE     (1 << 2)
+
 extern enum radeon_tv_std
 radeon_combios_get_tv_info(struct radeon_device *rdev);
 extern enum radeon_tv_std
@@ -531,6 +536,8 @@ extern int radeon_crtc_cursor_set(struct drm_crtc *crtc,
 extern int radeon_crtc_cursor_move(struct drm_crtc *crtc,
 				   int x, int y);
 
+extern int radeon_get_crtc_scanoutpos(struct radeon_device *rdev, int crtc, int *vpos, int *hpos);
+
 extern bool radeon_combios_check_hardcoded_edid(struct radeon_device *rdev);
 extern struct edid *
 radeon_combios_get_hardcoded_edid(struct radeon_device *rdev);