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authorDavid S. Miller <davem@davemloft.net>2017-06-15 11:31:37 -0400
committerDavid S. Miller <davem@davemloft.net>2017-06-15 11:59:32 -0400
commit0ddead90b223faae475f3296a50bf574b7f7c69a (patch)
treee729c7fcdc7e3697f7fae2f3028ed0d11931c425 /drivers/gpu/drm/i915/intel_display.c
parentf7aec129a356ad049edddcb7e77b04a474fcf41f (diff)
parenta090bd4ff8387c409732a8e059fbf264ea0bdd56 (diff)
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Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
The conflicts were two cases of overlapping changes in batman-adv and the qed driver. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/gpu/drm/i915/intel_display.c')
-rw-r--r--drivers/gpu/drm/i915/intel_display.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 3cabe52a4e3b..569717a12723 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -12203,6 +12203,15 @@ static void update_scanline_offset(struct intel_crtc *crtc)
* type. For DP ports it behaves like most other platforms, but on HDMI
* there's an extra 1 line difference. So we need to add two instead of
* one to the value.
+ *
+ * On VLV/CHV DSI the scanline counter would appear to increment
+ * approx. 1/3 of a scanline before start of vblank. Unfortunately
+ * that means we can't tell whether we're in vblank or not while
+ * we're on that particular line. We must still set scanline_offset
+ * to 1 so that the vblank timestamps come out correct when we query
+ * the scanline counter from within the vblank interrupt handler.
+ * However if queried just before the start of vblank we'll get an
+ * answer that's slightly in the future.
*/
if (IS_GEN2(dev_priv)) {
const struct drm_display_mode *adjusted_mode = &crtc->config->base.adjusted_mode;