diff options
Diffstat (limited to 'drivers/gpu/drm/i915/i915_irq.c')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_irq.c | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index 6a07ef38fb47..0b7562135d1c 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -783,6 +783,57 @@ static u32 g4x_get_vblank_counter(struct drm_device *dev, unsigned int pipe) return I915_READ(PIPE_FRMCOUNT_G4X(pipe)); } +/* + * On certain encoders on certain platforms, pipe + * scanline register will not work to get the scanline, + * since the timings are driven from the PORT or issues + * with scanline register updates. + * This function will use Framestamp and current + * timestamp registers to calculate the scanline. + */ +static u32 __intel_get_crtc_scanline_from_timestamp(struct intel_crtc *crtc) +{ + struct drm_i915_private *dev_priv = to_i915(crtc->base.dev); + struct drm_vblank_crtc *vblank = + &crtc->base.dev->vblank[drm_crtc_index(&crtc->base)]; + const struct drm_display_mode *mode = &vblank->hwmode; + u32 vblank_start = mode->crtc_vblank_start; + u32 vtotal = mode->crtc_vtotal; + u32 htotal = mode->crtc_htotal; + u32 clock = mode->crtc_clock; + u32 scanline, scan_prev_time, scan_curr_time, scan_post_time; + + /* + * To avoid the race condition where we might cross into the + * next vblank just between the PIPE_FRMTMSTMP and TIMESTAMP_CTR + * reads. We make sure we read PIPE_FRMTMSTMP and TIMESTAMP_CTR + * during the same frame. + */ + do { + /* + * This field provides read back of the display + * pipe frame time stamp. The time stamp value + * is sampled at every start of vertical blank. + */ + scan_prev_time = I915_READ_FW(PIPE_FRMTMSTMP(crtc->pipe)); + + /* + * The TIMESTAMP_CTR register has the current + * time stamp value. + */ + scan_curr_time = I915_READ_FW(IVB_TIMESTAMP_CTR); + + scan_post_time = I915_READ_FW(PIPE_FRMTMSTMP(crtc->pipe)); + } while (scan_post_time != scan_prev_time); + + scanline = div_u64(mul_u32_u32(scan_curr_time - scan_prev_time, + clock), 1000 * htotal); + scanline = min(scanline, vtotal - 1); + scanline = (scanline + vblank_start) % vtotal; + + return scanline; +} + /* I915_READ_FW, only for fast reads of display block, no need for forcewake etc. */ static int __intel_get_crtc_scanline(struct intel_crtc *crtc) { @@ -799,6 +850,9 @@ static int __intel_get_crtc_scanline(struct intel_crtc *crtc) vblank = &crtc->base.dev->vblank[drm_crtc_index(&crtc->base)]; mode = &vblank->hwmode; + if (mode->private_flags & I915_MODE_FLAG_GET_SCANLINE_FROM_TIMESTAMP) + return __intel_get_crtc_scanline_from_timestamp(crtc); + vtotal = mode->crtc_vtotal; if (mode->flags & DRM_MODE_FLAG_INTERLACE) vtotal /= 2; |