drm/i915: Fix gen2 and hsw+ scanline counter
On gen2 the scanline counter behaves a bit differently from the
later generations. Instead of adding one to the raw scanline
counter value, we must subtract one.
On HSW/BDW the scanline counter requires a +2 adjustment on HDMI
outputs. DP outputs on the on the other require the typical +1
adjustment.
As the fixup we must apply to the hardware scanline counter
depends on several factors, compute the desired offset at modeset
time and tuck it away for when it's needed.
v2: Clarify HSW+ situation
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: "Akash Goel <akash.goels@gmail.com>"
Reviewed-by: "Sourab Gupta <sourabgupta@gmail.com>"
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=78997
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 287b89e..d7c52b2 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -409,6 +409,8 @@
} wm;
wait_queue_head_t vbl_wait;
+
+ int scanline_offset;
};
struct intel_plane_wm_parameters {