[PATCH 7/9] drm/i915: Improve gen3/4 frame counter

ville.syrjala
2014-04-29T10:36:17Z

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

Currently the logic to fix up the frame counter on gen3/4 assumes that
start of vblank occurs at vblank_start*htotal pixels, when in fact
it occurs htotal-hsync_start pixels earlier. Apply the appropriate
adjustment to make the frame counter more accurate.

Also fix the vblank start position for interlaced display modes.

Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
drivers/gpu/drm/i915/i915_irq.c | 21 ++++++++++++++++-----
1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 64cd888..742f276 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -683,7 +683,7 @@ static u32 i915_get_vblank_counter(struct drm_device *dev, int pipe)
struct drm_i915_private *dev_priv = dev->dev_private;
unsigned long high_frame;
unsigned long low_frame;
- u32 high1, high2, low, pixel, vbl_start;
+ u32 high1, high2, low, pixel, vbl_start, hsync_start, htotal;

if (!i915_pipe_enabled(dev, pipe)) {
DRM_DEBUG_DRIVER("trying to get vblank count for disabled "
@@ -697,17 +697,28 @@ static u32 i915_get_vblank_counter(struct drm_device *dev, int pipe)
const struct drm_display_mode *mode =
&intel_crtc->config.adjusted_mode;

- vbl_start = mode->crtc_vblank_start * mode->crtc_htotal;
+ htotal = mode->crtc_htotal;
+ hsync_start = mode->crtc_hsync_start;
+ vbl_start = mode->crtc_vblank_start;
+ if (mode->flags & DRM_MODE_FLAG_INTERLACE)
+ vbl_start = DIV_ROUND_UP(vbl_start, 2);
} else {
enum transcoder cpu_transcoder = (enum transcoder) pipe;
- u32 htotal;

htotal = ((I915_READ(HTOTAL(cpu_transcoder)) >> 16) & 0x1fff) + 1;
+ hsync_start = (I915_READ(HSYNC(cpu_transcoder)) & 0x1fff) + 1;
vbl_start = (I915_READ(VBLANK(cpu_transcoder)) & 0x1fff) + 1;
-
- vbl_start *= htotal;
+ if ((I915_READ(PIPECONF(cpu_transcoder)) &
+ PIPECONF_INTERLACE_MASK) != PIPECONF_PROGRESSIVE)
+ vbl_start = DIV_ROUND_UP(vbl_start, 2);
}

+ /* Convert to pixel count */
+ vbl_start *= htotal;
+
+ /* Start of vblank event occurs at start of hsync */
+ vbl_start -= htotal - hsync_start;
+
high_frame = PIPEFRAME(pipe);
low_frame = PIPEFRAMEPIXEL(pipe);

--
1.8.3.2