torsdag 3 april 2014

Installing Linux on a tablet

Tablets usually have only a few USB ports. The Viewsonic Viewpad 10pi has two. I'll show later that this makes things a bit complicated.

Because of the badly supported hardware in Z670 tablets, you have to improvise a few things. The graphics chip doesn't necessary let the installer run in grahical mode and the Wi-fi chip is not detected automatically by the installer.

I first tried installing Fedora 20. It failed, because the Wi-fi chip was not detected and the installer refused to continue without a configured network device (at least the text mode installer, because the graphical installer refused to run). Using an external USB Wi-fi device helped, but Fedora fails to start X-windows on this graphics chip. I'm not sure what the problem is. It doesn't load the required module, gma500_gfx, automatically. Loading it manually doesn't help.

Then I tried Debian. It turned out that Debian automatically loads the graphical driver and it is possible to start X. This is how I did it:

1. Download debian-7.4.0-i386-netinst.iso and put it on an USB stick.  Just copy the ISO to your USB with
cp debian-7.4.0-i386-netinst.iso /dev/sdX

The driver for the network card is available in firmware-libertas backports (mwifiex_sdio). I wasn't able to use it during installation. I had to use a separate USB wifi device and an USB hub. Not sure what the problem was, but it began working after installation.

2. Connect an USB keyboard to the tablet. Boot the tablet  with the USB stick. Press F9 to boot the USB. 

3. Install Debian normally.

Debian Wheezy will start Gnome in fallback mode (without grahipcs hardware acceleration), and unfortunately on-screen keyboard doesn't work at the login screen in fallback mode.

I also tried Debian Jessie Alpha 1, but there was a bug with gdm and I couldn't start any desktop (I tried gnome and lightdm). Instead I had to switch to lightdm-greeter and start gnome that way. Unfortunately there was no on-screen keyboard support for lightdm-greeter, so I had to enable auto-login.

You wonder of course how I did all that without logging in, but I was in fact logged in, from another PC with ssh. All you need is a terminal and ssh server running on the tablet.

Jessie also had another bug, the panel in gnome wasn't working with the touch screen.

To be continued...