MPlayer-0.90rc2 on an 8Mb ATI Rage Mobility M3 detects the video memory as "0Mb" using the rage128_vid xvidix driver. I fixed this by changing CONFIG_MEMSIZE_MASK in vidix/drivers/radeon.h line 1296 from 0x1f000000 to 0x1fc00000. This seems to be necessary to detect any video memory size that is a multiple of 8Mb.