drm/i915: Add support for precise vblank timestamping (v2)
v2: Change IS_IRONLAKE to IS_GEN5 to adapt to 2.6.37
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.
.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 patch modifies the pageflip completion routine
to use these precise vblank timestamps as the timestamps
for pageflip completion events.
This code has been only tested on a HP-Mini Netbook with
Atom processor and Intel 945GME gpu. The codepath for
(IS_G4X(dev) || IS_GEN5(dev) || IS_GEN6(dev)) gpu's
has not been tested so far due to lack of hardware.
Signed-off-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index e4a2e2c..adf983f 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -248,6 +248,92 @@
return I915_READ(reg);
}
+int i915_get_crtc_scanoutpos(struct drm_device *dev, int pipe,
+ int *vpos, int *hpos)
+{
+ drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+ u32 vbl = 0, position = 0;
+ int vbl_start, vbl_end, htotal, vtotal;
+ bool in_vbl = true;
+ int ret = 0;
+
+ if (!i915_pipe_enabled(dev, pipe)) {
+ DRM_DEBUG_DRIVER("trying to get scanoutpos for disabled "
+ "pipe %d\n", pipe);
+ return 0;
+ }
+
+ /* Get vtotal. */
+ vtotal = 1 + ((I915_READ(VTOTAL(pipe)) >> 16) & 0x1fff);
+
+ if (INTEL_INFO(dev)->gen >= 4) {
+ /* No obvious pixelcount register. Only query vertical
+ * scanout position from Display scan line register.
+ */
+ position = I915_READ(PIPEDSL(pipe));
+
+ /* Decode into vertical scanout position. Don't have
+ * horizontal scanout position.
+ */
+ *vpos = position & 0x1fff;
+ *hpos = 0;
+ } else {
+ /* Have access to pixelcount since start of frame.
+ * We can split this into vertical and horizontal
+ * scanout position.
+ */
+ position = (I915_READ(PIPEFRAMEPIXEL(pipe)) & PIPE_PIXEL_MASK) >> PIPE_PIXEL_SHIFT;
+
+ htotal = 1 + ((I915_READ(HTOTAL(pipe)) >> 16) & 0x1fff);
+ *vpos = position / htotal;
+ *hpos = position - (*vpos * htotal);
+ }
+
+ /* Query vblank area. */
+ vbl = I915_READ(VBLANK(pipe));
+
+ /* Test position against vblank region. */
+ vbl_start = vbl & 0x1fff;
+ vbl_end = (vbl >> 16) & 0x1fff;
+
+ if ((*vpos < vbl_start) || (*vpos > vbl_end))
+ in_vbl = false;
+
+ /* Inside "upper part" of vblank area? Apply corrective offset: */
+ if (in_vbl && (*vpos >= vbl_start))
+ *vpos = *vpos - vtotal;
+
+ /* Readouts valid? */
+ if (vbl > 0)
+ ret |= DRM_SCANOUTPOS_VALID | DRM_SCANOUTPOS_ACCURATE;
+
+ /* In vblank? */
+ if (in_vbl)
+ ret |= DRM_SCANOUTPOS_INVBL;
+
+ return ret;
+}
+
+int i915_get_vblank_timestamp(struct drm_device *dev, int crtc,
+ int *max_error,
+ struct timeval *vblank_time,
+ unsigned flags)
+{
+ struct drm_crtc *drmcrtc;
+
+ if (crtc < 0 || crtc >= dev->num_crtcs) {
+ DRM_ERROR("Invalid crtc %d\n", crtc);
+ return -EINVAL;
+ }
+
+ /* Get drm_crtc to timestamp: */
+ drmcrtc = intel_get_crtc_for_pipe(dev, crtc);
+
+ /* Helper routine in DRM core does all the work: */
+ return drm_calc_vbltimestamp_from_scanoutpos(dev, crtc, max_error,
+ vblank_time, flags, drmcrtc);
+}
+
/*
* Handle hotplug events outside the interrupt handler proper.
*/