I've begun testing 4.0 kernel on QNAP TS-212P. The following results likely apply also to other devices matching kirkwood-ts219-6282.dtb like TS-210 and variants of TS-219. So, let's begin with...
The Good: * mv_cesa works correctly (partially broken in 3.16 - #783718) * kirkwood-cpufreq works correctly (it didn't seem to do anything in 3.16) * kirkwood-thermal works correctly (/sys/class/thermal/thermal_zone0 is correctly populated, nothing in 3.16) The Bad: * qcontrol service does not start. This appears to be due to the fact that qcontrol expects a symlink "platform-gpio-keys-event" in /dev/input/by-path, while with the 4.0 kernel it's called "platform-gpio_keys-event" instead. As a workaround, adding the expected symlink causes qcontrol to work correctly (warning: without qcontrol the device is on a 5 minute watchdog, you can also interrupt it with "echo -n g >/dev/ttyS1"). The Ugly: * USB 3.0 doesn't seem to work - xhci doesn't start correctly: [ 10.163137] xhci_hcd 0000:02:00.0: xHCI Host Controller [ 10.185235] xhci_hcd 0000:02:00.0: new USB bus registered, assigned bus number 3 [ 10.230163] xhci_hcd 0000:02:00.0: Host took too long to start, waited 16000 microseconds. [ 10.238481] xhci_hcd 0000:02:00.0: startup error -19 [ 10.322217] xhci_hcd 0000:02:00.0: USB bus 3 deregistered [ 10.346872] xhci_hcd 0000:02:00.0: remove, state 1 * I am experiencing system instability following flash-kernel on kernel update: rm: cannot remove ‘/tmp/flash-kernel.VuR9vASl’: Read-only file system run-parts: /etc/initramfs/post-update.d//flash-kernel exited with return code 1 dpkg: error: unable to create new file '/var/lib/dpkg/status-new': Read-only file system At this point any commands end with segmentation faults and input/output errors. The flashing process seems to complete correctly though. That's all for now. Best regards, Jan