Friday, 21 May 2010

Joggler Hardware Gotchas

I haven't (so far at least) attempted to modify my Joggler hardware in any way. It is possible to do so in order to, for example, add an internal USB port. If you're interested in this sort of thing then have a look at the Hacking the Hardware section over at the Joggler Wiki. I have spent a reasonable amount of time playing with the hardware now though so here's my list of things to be careful about.

GMA 500
Contrary to Intel's usual position with regards Linux support, the GMA 500 chipset is an absolute abomination.  The basic reason for this is they license some of the technology from elsewhere so are unable to provide the full source code to the community.  This means parts of the drivers for the GMA 500 chipset are binary only, cannot be shipped by any of the Linux distributions, so must be downloaded individually by each user.  This driver is known as IEGD (Intel Embedded Graphics Driver).

There is an open source alternative known as PSB (or the Poulsbo driver).  Support for this in the Linux distributions is patchy at best.  Earlier versions of Ubuntu and Fedora have better support for this driver as it best supports earlier versions of Xorg, namely version 1.6.4 and below.  The PSB driver has very recently been patched to support Xorg 1.7 and later so should soon start to work with Fedora 12 and above and Ubuntu 10.04.  The patch was written by someone in the Mandriva community and has been made available for Fedora 12/13 by a Red Hat employee netbook enthusiast.

I have tried both drivers on Fedora 12.  I was unable to get Adam's PSB driver to work (the akmod failed to compile) but I do have a fully working Fedora 12 graphical system using the IEGD driver.  There will be more about how to get all that going in another blog post soon.

It's a shame the Joggler (and most netbooks) use this chipset.  Before investigating you would think Linux would have superb support for Atom based netbooks given many of them have previously been sold with a Linux pre-install version.  My guess is the lack of support for current distributions is why we don't see new Linux pre-install netbooks any more.  This can only be due to demand though, Intel would support later versions if a vendor was willing to pay for support but the market has to be there in order to make this worthwhile (rant over).

USB power
The power provided by the Joggler's USB port is dodgy (technical term) at best.  In order to support that claim I have tried several different USB hard disks (1 Lenovo, and 2 Freecom disks) and only non-bus-powered ones have worked reliably.  The Joggler simply isn't able to provide enough power to operate these drives, two that I tried span up but didn't get enough power to move the disk heads, the third (a brand new Freecom mobile drive classic 2) does work but occasionally drops out causing the OS to crash.  My recommendation is to provide an external power source if you're connecting much more than a USB stick to your Joggler.

Options then, well you can either mains power your device(s) or power from a USB hub.  Either of these work reliably in my experience (I've tried a mains powered 3½" disk and powered hubs with my 2½" disks) but still there's one more problem.  If your device passes power back into the Joggler itself, it wont boot and you'll end up in the O2 interface.  You'll know if your device is doing this as the Joggler backlight will be lit even if the Joggler is not plugged into the mains! So now you have 2 options again, (1) stop your device passing power back to the Joggler, and (2) butcher a USB cable.

You can stop your device from passing power back to the Joggler (if it is doing so) by buying a decent powered USB hub. I'm using a Plexus hub I bought from eBuyer along with my Freecom disk.  I have tried some cheaper powered hubs but they also passed power back to the host so while allowing me to connect multiple devices didn't solve the problem I was having.

The USB cable butchery option isn't as bad as it sounds.  USB cables have 4 wires in them, white and green for data, black for earth and red for live.  Simply grab the cable you want to connect your device with (whether it's the device itself or a cheaper powered hub which is passing power back to the Joggler), cut part of the outer sheath away (about an inch will do) somewhere along the cable length, find the 4 cables inside (getting through any braiding or foil that might be in your cable depending on how expensive it was), then simply cut the live wire.  Make sure the live ends are not touching each other with some insulation and you can wrap the cable back up again.  That's it, you've now got a Joggler compatible USB cable which wont pass power back to the Joggler but, obviously, wont power your device either.  The Joggler is able to detect you've got a drive as part of the circuit is still there via the ground cable and data will flow as normal along the untouched data cables.

This observation is a real oddity for which I have no explanation (suggestions welcome).  The Joggler will not boot from your USB device if it has 4 primary partitions, don't ask me why, yes it should work, but it just doesn't boot.  Using 3 primary partitions works, up to 2 primary partitions, an extended partition and as many logical partitions as you like also works.  But, give it a device with 4 partitions on and it's game over as far as booting from that device is concerned.

Some people have mentioned to me about not finding the touch screen very user friendly while running Linux. When compared with the O2 interface that's a pretty fair comment as things tend to be a lot smaller on Linux vs O2. There are various tweaks you can make to your desktop depending on your personal preference such as:
  • finding an on-screen keyboard you're happy with (onBoard vs Cellwriter for example)
  • increasing the font size such that all the things you want to touch (click on) are bigger (do this under System->Preferences->Appearance->Fonts in Gnome)
  • installing touch screen addons for your programs (such as chromeTouch for Chrome)
  • Make your scrollbars wider
If you've decided the touch screen really isn't for you then look into getting a keyboard/mouse solution or a stylus. For keyboards/mice you'll need a USB hub so you're able to attach more than one device to your joggler. I have and can recommend a wireless BTC keyboard with built in joystick (for mouse control) which uses a radio signal via a USB receiver. You can use any USB keyboard/mouse you like though but I'd recommend something compact and wireless, there's always Bluetooth too for which you can get some pretty tiny receivers these days. If you go for the stylus option there's plenty of commercial solutions out there for capacitive touch screens. I quite like this DIY Stylus as an option, however.

You can find a lot more of my information about the Joggler at my Joggler Index post. I also have a list of Joggler Bookmarks.

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