drm/radeon: add a module parameter to disable aspm

Can cause hangs when enabled in certain motherboards.
Set radeon.aspm=0 to disable aspm.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
drm/radeon: fix an endian bug in atom table parsing

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
drm/radeon/dpm: fix atom vram table parsing

Parsing the table in incorrectly led to problems with
certain asics with mclk switching.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
drm/radeon/dpm/atom: restructure logic to work around a compiler bug

It seems gcc 4.8.1 generates bogus code for the old logic causing
part of the function to get skipped.

Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=66932
https://bugs.freedesktop.org/show_bug.cgi?id=66972
https://bugs.freedesktop.org/show_bug.cgi?id=66945

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
drm/radeon/dpm/atom: fix broken gcc harder

See bugs:
https://bugs.freedesktop.org/show_bug.cgi?id=66932
https://bugs.freedesktop.org/show_bug.cgi?id=66972
https://bugs.freedesktop.org/show_bug.cgi?id=66945

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
drm/radeon/dpm: add debugfs support for RS780/RS880 (v3)

This allows you to look at the current DPM state via
debugfs.

Due to the way the hardware works on these asics, there's
no way to look up exactly what power state we are in, so
we make the best guess we can based on the current sclk.

v2: Anthoine's version
v3: fix ref div

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>