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drm/i915: Add support for precise vblank timestamping (v2)

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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>
This commit is contained in:
Mario Kleiner
2010-12-08 04:07:19 +01:00
committed by Chris Wilson
parent d8c58fabd7
commit 0af7e4dff5
5 changed files with 119 additions and 6 deletions
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86
drivers/gpu/drm/i915/i915_irq.c
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@@ -248,6 +248,92 @@ u32 gm45_get_vblank_counter(struct drm_device *dev, int pipe)
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.
*/