[PATCH 3.16.y-ckt 081/165] drm/radeon: fix interlaced modes on DCE8

[Luis Henriques]

3.16.7-ckt9 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alex Deucher <alexander.deucher at amd.com>

commit 77ae5f4b48a0445426c9c1ef7c0f28b717e35d55 upstream.

Need to double the viewport height.

Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/gpu/drm/radeon/atombios_crtc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
index dce0d3918fa7..9f0e62529c46 100644
--- a/drivers/gpu/drm/radeon/atombios_crtc.c
+++ b/drivers/gpu/drm/radeon/atombios_crtc.c
@@ -1405,6 +1405,9 @@ static int dce4_crtc_do_set_base(struct drm_crtc *crtc,
 	       (x << 16) | y);
 	viewport_w = crtc->mode.hdisplay;
 	viewport_h = (crtc->mode.vdisplay + 1) & ~1;
+	if ((rdev->family >= CHIP_BONAIRE) &&
+	    (crtc->mode.flags & DRM_MODE_FLAG_INTERLACE))
+		viewport_h *= 2;
 	WREG32(EVERGREEN_VIEWPORT_SIZE + radeon_crtc->crtc_offset,
 	       (viewport_w << 16) | viewport_h);