after some adjustments, everything EXCEPT bluetooth seems to work perfectly.
Graphics Adapter AMD Radeon HD 7420G : double display with separate resolutions, extended desktop works perfectly with XFCE.
[ not tested: HDMI Audio output ]
|What doesn't work:|
(1) skype audio does not work (no sound at all or awful crackling)
(2) Cinnamon/Mate Desktops: Double Display with separate resolutions does not consistently work (resets after reboot, if secondary monitor is not powered)
(3) on resume after suspend the display remains dead. Need to choke the system with power botton.
(4) Bluetooth does not work at all (Atheros 9485 WLAN works properly, however hardware switch does not work)
|What was done to make it work:|
(1) installed package libpulse0:i386 -> skype audio ok
(2) install fglrx-updates
(a) edited /etc/default/grub :
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_backlight=vendor"
(b) sudo update-grub
(4) no solution so far (seems to be a known / unsolved problem)
fair result for crappy hardware (I never had any atheros wifi/bt device that worked out of the box...)