In the 12.04 Xorg.0.log I have the line
[ 39.624] (II) RADEON(0): Color tiling enabled by default
If it was using KMS then it should be (*I think*) something like ths:
[ 98.582] (II) RADEON(0): KMS Color Tiling: disabled [ 98.582] (II) RADEON(0): KMS Pageflipping: enabled
This is why I think 12.04 uses UMS even though the dmesg says KMS is enabled.
In the 12.04 Xorg.0.log I have the line
[ 39.624] (II) RADEON(0): Color tiling enabled by default
If it was using KMS then it should be (*I think*) something like ths:
[ 98.582] (II) RADEON(0): KMS Color Tiling: disabled
[ 98.582] (II) RADEON(0): KMS Pageflipping: enabled
This is why I think 12.04 uses UMS even though the dmesg says KMS is enabled.