Created attachment 132031 [details]
I have a ASUS K53TK with a AMD A6-3420M. It has an integrated graphics card the AMD HD 6520G, and a dedicated one HD 7670M.
I am only able to use the dedicated card if I set the parameter "radeon.runpm=0".
Otherwise xrandr only sees one provider, and DRI_PRIME=1 can't render any program.
At boot time, if I don't disable the power management I get several error like [ 458.460874] [drm:r600_ring_test [radeon]] *ERROR* radeon: ring 0 test failed (scratch(0x8504)=0xFFFFFFFF).
Created attachment 132032 [details]
lspci -k output
Created attachment 132063 [details] [review]
PX is known to be broken on K53TK systems. Add a quirk for another variant.