Why Does 14.04 Hate AMD?

[Ralf Mardorf]

Several Linux PREEMPT RT users with AMD CPUs experienced issues,
independent of the used disto/WM/DE. The only rt patched kernel I can
use > 3.8.x is 3.10.47-rt50. Linux-rt <= 3.8.x are ok, but > 3.8 don't
work on my machine [1], excepted of the 3.10.47 with the 50th patch.
There were no issues with vanilla kernels <= 3.16.

To put it in a nutshell, did you test older kernels? Did you disable
options in GRUB's kernel line or build kernels with new features
disabled?

> It seems that AMD64 is a red-headed stepchild for some
> reason.

The kernel developer might not have all the AMD hardware they need for
testing and even if they would have, they perhaps don't have enough
time. It's up to the community to help debugging kernels. Unfortunately
I couldn't help, since not only knowledge is needed, but also hardware.
When the machine logs and there are no useful log files, no debugging
information, connecting another computer by parallel port and things
like this are needed, to give the developer the information they need.

Troubleshooting: Did you test another DE, or better a lightweight WM
that is known to be stable?

[1]
# grep "model name" /proc/cpuinfo 
model name	: AMD Athlon(tm) X2 Dual Core Processor BE-2350
model name	: AMD Athlon(tm) X2 Dual Core Processor BE-2350