madmalkav, your dmesg log had messages from the fglrx kernel driver... not
saying that *is* your problem but it definitely can't help... any chance you
can test on a vanilla system that hasn't had fglrx installed ?

[    9.614226] <6>[fglrx] Maximum main memory to use for locked dma buffers:
7714 MBytes.
[    9.614510] <6>[fglrx]   vendor: 1002 device: 679e revision: 0 count: 1
[    9.615005] <6>[fglrx] ioport: bar 4, base 0xe000, size: 0x100
[    9.615248] <6>[fglrx] Kernel PAT support is enabled
[    9.615263] <6>[fglrx] module loaded - fglrx 15.20.3 [Sep  8 2015] with 1
minors