[PATCH 4/6] drm/cirrus: Proper support for depth 15 and 16

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

We were configuring SR7 very strangely for 16bpp and didn't properly
differenciate between depth 15 and 16. This fixes it (and both
appear to work at least on ppc)

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
 drivers/gpu/drm/cirrus/cirrus_mode.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/cirrus/cirrus_mode.c b/drivers/gpu/drm/cirrus/cirrus_mode.c
index e3d2dc0..1566853 100644
--- a/drivers/gpu/drm/cirrus/cirrus_mode.c
+++ b/drivers/gpu/drm/cirrus/cirrus_mode.c
@@ -269,13 +269,14 @@ static int cirrus_crtc_mode_set(struct drm_crtc *crtc,
 	sr07 = RREG8(SEQ_DATA);
 	sr07 &= 0xe0;
 	hdr = 0;
+
 	switch (crtc->fb->bits_per_pixel) {
 	case 8:
 		sr07 |= 0x11;
 		break;
 	case 16:
-		sr07 |= 0xc1;
-		hdr = 0xc0;
+		sr07 |= 0x17;
+		hdr = (crtc->fb->depth == 16) ? 0xc1 : 0xc0;
 		break;
 	case 24:
 		sr07 |= 0x15;