[PATCH] drm/nv50/disp: use correct register to determine DP display bpp

[Ilia Mirkin]

Commit 0a0afd282f ("drm/nv50-/disp: move DP link training to core and
train from supervisor") added code that uses the wrong register for
computing the display bpp, used for bandwidth calculation. Adjust to use
the same register as used by exec_clkcmp and nv50_disp_intr_unk20_2_dp.

Reported-by: Torsten Wagner <torsten.wagner at gmail.com>
Reported-by: Michael Gulick <mgulick at mathworks.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=67628
Cc: stable at vger.kernel.org # 3.9+
Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
---

Ben did a quick test that makes it seem like this is the right thing to
do. And it makes sense based on the surrounding code, and the way in which the
regression manifests itself.

 drivers/gpu/drm/nouveau/core/engine/disp/nv50.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/core/engine/disp/nv50.c b/drivers/gpu/drm/nouveau/core/engine/disp/nv50.c
index 940eaa5..9ad722e 100644
--- a/drivers/gpu/drm/nouveau/core/engine/disp/nv50.c
+++ b/drivers/gpu/drm/nouveau/core/engine/disp/nv50.c
@@ -1142,7 +1142,7 @@ nv50_disp_intr_unk20_2(struct nv50_disp_priv *priv, int head)
 	if (conf != ~0) {
 		if (outp.location == 0 && outp.type == DCB_OUTPUT_DP) {
 			u32 soff = (ffs(outp.or) - 1) * 0x08;
-			u32 ctrl = nv_rd32(priv, 0x610798 + soff);
+			u32 ctrl = nv_rd32(priv, 0x610794 + soff);
 			u32 datarate;
 
 			switch ((ctrl & 0x000f0000) >> 16) {
-- 
1.8.3.2