Mesa (master): nvc0: reintroduce BGRA4 format support

[Ilia Mirkin]

Module: Mesa
Branch: master
Commit: d68226087cf5f2f686d6c8f3377c5a1dec3d8bc4
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=d68226087cf5f2f686d6c8f3377c5a1dec3d8bc4

Author: Ilia Mirkin <imirkin at alum.mit.edu>
Date:   Thu Nov  5 23:12:52 2015 -0500

nvc0: reintroduce BGRA4 format support

Commit 342e68dc60 (nvc0: remove BGRA4 format support) removed the
support to fix a WoW trace. However after further experimentation, I was
able to get the blit to work by using a different "fake" format in the
2d engine.

The reason why this worked on nv50 is that nv50 falls back to the 3d
blit path in case either the src or the dst aren't "faithfully"
supported, while nvc0 only does it for the dst format. RG8 is better
supported by the nvc0 2d engine than R16.

Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>

---

 src/gallium/drivers/nouveau/nv50/nv50_formats.c |    2 --
 src/gallium/drivers/nouveau/nvc0/nvc0_surface.c |    2 +-
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/src/gallium/drivers/nouveau/nv50/nv50_formats.c b/src/gallium/drivers/nouveau/nv50/nv50_formats.c
index 80f92be..49a93bf 100644
--- a/src/gallium/drivers/nouveau/nv50/nv50_formats.c
+++ b/src/gallium/drivers/nouveau/nv50/nv50_formats.c
@@ -203,10 +203,8 @@ const struct nv50_format nv50_format_table[PIPE_FORMAT_COUNT] =
    F3B(B5G6R5_UNORM, B5G6R5_UNORM, C2, C1, C0, xx, UNORM, 5_6_5, TD),
    C4B(B5G5R5A1_UNORM, BGR5_A1_UNORM, C2, C1, C0, C3, UNORM, 5_5_5_1, TD),
    F3B(B5G5R5X1_UNORM, BGR5_X1_UNORM, C2, C1, C0, xx, UNORM, 5_5_5_1, TD),
-#if NOUVEAU_DRIVER != 0xc0
    C4B(B4G4R4A4_UNORM, NONE, C2, C1, C0, C3, UNORM, 4_4_4_4, T),
    F3B(B4G4R4X4_UNORM, NONE, C2, C1, C0, xx, UNORM, 4_4_4_4, T),
-#endif
    F3B(R9G9B9E5_FLOAT, NONE, C0, C1, C2, xx, FLOAT, 9_9_9_E5, T),
 
    C4A(R10G10B10A2_UNORM, RGB10_A2_UNORM, C0, C1, C2, C3, UNORM, 10_10_10_2,
diff --git a/src/gallium/drivers/nouveau/nvc0/nvc0_surface.c b/src/gallium/drivers/nouveau/nvc0/nvc0_surface.c
index be12334..5f47bad 100644
--- a/src/gallium/drivers/nouveau/nvc0/nvc0_surface.c
+++ b/src/gallium/drivers/nouveau/nvc0/nvc0_surface.c
@@ -67,7 +67,7 @@ nvc0_2d_format(enum pipe_format format, bool dst, bool dst_src_equal)
    case 1:
       return NV50_SURFACE_FORMAT_R8_UNORM;
    case 2:
-      return NV50_SURFACE_FORMAT_R16_UNORM;
+      return NV50_SURFACE_FORMAT_RG8_UNORM;
    case 4:
       return NV50_SURFACE_FORMAT_BGRA8_UNORM;
    case 8: