drm/gf110-/disp: magic that might help some tmds issues

The binary driver has been doing this since GF119, and we've somehow
gotten away with it.  But, TMDS that hasn't been initialised already
by the x86 vbios code is distorted without it on GM204.
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/core/engine/disp/nvd0.c

@@ -1063,10 +1063,18 @@ nvd0_disp_intr_unk2_2(struct nv50_disp_priv *priv, int head)
 		addr = 0x612280 + (ffs(outp->info.or) - 1) * 0x800;
 		data = 0x00000000;
 	} else {
-		if (outp->info.type == DCB_OUTPUT_DP)
-			nvd0_disp_intr_unk2_2_tu(priv, head, &outp->info);
 		addr = 0x612300 + (ffs(outp->info.or) - 1) * 0x800;
 		data = (conf & 0x0100) ? 0x00000101 : 0x00000000;
+		switch (outp->info.type) {
+		case DCB_OUTPUT_TMDS:
+			nv_mask(priv, addr, 0x007c0000, 0x00280000);
+			break;
+		case DCB_OUTPUT_DP:
+			nvd0_disp_intr_unk2_2_tu(priv, head, &outp->info);
+			break;
+		default:
+			break;
+		}
 	}
 
 	nv_mask(priv, addr, 0x00000707, data);