I tried to add the resolution with xrandr and then setting it but it gives the no gamma recognized error.
I tried with 12.04 beta and 11.10 with no results.
Also it seems that there's not much info about this model.
The x101ch uses a new graphics driver, the GMA3600. Kernel drivers for the GMA3600 are still experimental and have not made it into the kernels that are in Ubuntu's repositories yet. Because your kernel doesn't have the drivers it falls back to using the default resolution, 800x600.
You've got two options:
1) Wait for the GMA3600 drivers to make it into mainline, easy enough...
2) Compile the kernel with the experimental drivers. This isn't as hard as it sounds, especially since someone has already done it. The kernel produced through that guide works fine with the x101ch, has wireless drivers and everything. If you've not compiled a kernel before you may need to go install some packages.
Let me know if you have problems following the guide...
