drm/radeon/kms: fix r300 vram width calculations

This was incorrect according to the docs and the UMS driver does
it like this.

Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/radeon/r300.c b/drivers/gpu/drm/radeon/r300.c
index e699e6d..43b55a0 100644 (file)
--- a/drivers/gpu/drm/radeon/r300.c
+++ b/drivers/gpu/drm/radeon/r300.c
@@ -506,11 +506,14 @@ void r300_vram_info(struct radeon_device *rdev)
 
        /* DDR for all card after R300 & IGP */
        rdev->mc.vram_is_ddr = true;
+
        tmp = RREG32(RADEON_MEM_CNTL);
-       if (tmp & R300_MEM_NUM_CHANNELS_MASK) {
-               rdev->mc.vram_width = 128;
-       } else {
-               rdev->mc.vram_width = 64;
+       tmp &= R300_MEM_NUM_CHANNELS_MASK;
+       switch (tmp) {
+       case 0: rdev->mc.vram_width = 64; break;
+       case 1: rdev->mc.vram_width = 128; break;
+       case 2: rdev->mc.vram_width = 256; break;
+       default:  rdev->mc.vram_width = 128; break;
        }
 
        r100_vram_init_sizes(rdev);