drm/kms/radeon: Add support for precise vblank timestamping.

This patch adds new functions for use by the drm core:

.get_vblank_timestamp() provides a precise timestamp
for the end of the most recent (or current) vblank
interval of a given crtc, as needed for the DRI2
implementation of the OML_sync_control extension.

It is a thin wrapper around the drm function
drm_calc_vbltimestamp_from_scanoutpos() which does
almost all the work and is shared across drivers.

.get_scanout_position() provides the current horizontal
and vertical video scanout position and "in vblank"
status of a given crtc, as needed by the drm for use by
drm_calc_vbltimestamp_from_scanoutpos().

The function is also used by the dynamic gpu reclocking
code to determine when it is safe to reclock inside vblank.

For that purpose radeon_pm_in_vbl() is modified to
accomodate a small change in the function prototype of
the radeon_get_crtc_scanoutpos() which is hooked up to
.get_scanout_position().

This code has been tested on AVIVO hardware, a RV530
(ATI Mobility Radeon X1600) in a Intel Core-2 Duo MacBookPro
and some R600 variant (FireGL V7600) in a single cpu
AMD Athlon 64 PC.

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

1 files changed, 21 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
index 8fbbe1c6ebbd..4bf423ca4c12 100644
--- a/drivers/gpu/drm/radeon/radeon_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_kms.c
@@ -277,6 +277,27 @@ void radeon_disable_vblank_kms(struct drm_device *dev, int crtc)
         radeon_irq_set(rdev);
 }
 
+int radeon_get_vblank_timestamp_kms(struct drm_device *dev, int crtc,
+                                    int *max_error,
+                                    struct timeval *vblank_time,
+                                    unsigned flags)
+{
+        struct drm_crtc *drmcrtc;
+        struct radeon_device *rdev = dev->dev_private;
+
+        if (crtc < 0 || crtc >= dev->num_crtcs) {
+                DRM_ERROR("Invalid crtc %d\n", crtc);
+                return -EINVAL;
+        }
+
+        /* Get associated drm_crtc: */
+        drmcrtc = &rdev->mode_info.crtcs[crtc]->base;
+
+        /* Helper routine in DRM core does all the work: */
+        return drm_calc_vbltimestamp_from_scanoutpos(dev, crtc, max_error,
+                                                     vblank_time, flags,
+                                                     drmcrtc);
+}
 
 /*
  * IOCTL.