[CuBox] Testing Kernels

There were some reports about Mubox (0.9.1) stop playing music after few hours of play. "Cannot submit urb (err = -27)" error would occur and mpd stops playback music. This seems to be a common problem in CuBox. On 3.6.9 kernel, the way we did is to increase vmalloc and coherent_pool in kernel parameters:

root@voyage-mubox:~# cat /proc/cmdline
console=ttyS0,115200n8 vmalloc=96M coherent_pool=48M root=/dev/mmcblk0p1 rootfstype=ext4 rootwait

If "(err = -27)" still occur, you may increase vmalloc=144M and coherent_pool=96M in /boot/boot.txt. Then, re-generate boot.scr by:

mkimage -A arm -O linux -T script -C none -a 0 -e 0 -n 'Boot Script' -d /boot/boot.txt /boot/boot.scr

And reboot to make the change effective.

In addition, we build a collection of testing kernels in http://mirror.voyage.hk/download/voyage-mubox/kernel/
To install the kernel to Voyage MuBox:
1. Copy uImage-<version> to /boot/uImage
2. tar -zxvf modules-<version>.tar.gz -C /

Here is the testing status of various kernels in our environment:
3.10.1-1.voyage : cannot submit urb (err = -18) when remountrw/remountro
3.10.0-1.voyage : cannot submit urb (err = -18) when remountrw/remountro
3.8.13-1.voyage-rt14 : cannot submit urb (err = -18) after few minutes of play. Some reports this kernel works almost perfectly.
3.8.11-1.voyage-rt8 : No problem more than 3 days of music playback

So far 3.8.11-1.voyage-rt8 is the most stable from our test. Please note that your mileage may vary.

All these kernels does not include latest Dove GPU and Kirkwood SPDIF codes. So these functionality are missed out as expected.