st/xorg: Use A8 format for depth 8 pixmaps.

The inconsistent bpp caused issues with UploadTo/DownloadFromScreen.

diff --git a/src/gallium/state_trackers/xorg/xorg_exa.c b/src/gallium/state_trackers/xorg/xorg_exa.c
index 0d60b963bf34f625381073d7431b7230fcc3a108..d6241aa19ea6d69336e7d3b395be6f2fdaecf19f 100644 (file)
--- a/src/gallium/state_trackers/xorg/xorg_exa.c
+++ b/src/gallium/state_trackers/xorg/xorg_exa.c
@@ -74,6 +74,9 @@ exa_get_pipe_format(int depth, enum pipe_format *format, int *bbp)
        assert(*bbp == 16);
        break;
     case 8:
+       *format = PIPE_FORMAT_A8_UNORM;
+       assert(*bbp == 8);
+       break;
     case 4:
     case 1:
        *format = PIPE_FORMAT_A8R8G8B8_UNORM; /* bad bad bad */