I discovered by accident today that the scroll switch on the top of the unit will adjust the screen brightness in X. It doesn’t seem to work in the console, and I’ve done nothing to tell X about it, but it works. Woohoo.

Combined with that and laptop-mode and powernowd, I think I’m going to get 3 to 3.5 hours of battery life on this thing.

Things I’m not sure how to do yet:

1. Adjust the brightness of the tc1100 screen in Linux
2. Display xvkbd (or another on-screen keyboard) when the display has been locked via xscreensaver or KDE’s screensaver
3. Make sure the ACPI thermal settings are correct
4. Find a journaling filesystem that behaves well with laptops

About the ACPI settings… it seems like the fan is running more than it ought to, and also that the unit is warmer than it should be at times. Out under (from memory) /proc/acpi/thermal/THRM, I can find the current temperature and also the temperatures at which different things (fans, I guess) are supposed to be turned on. Strange thing is, that file that shows the temperature zones shows different temperature zones at different times. Also, the /proc/acpi/fan area never says that any fan is on, even when I can hear them.

Odd.

On the filesystem front — back when ext2 was about as good as it got, I used to tweak the kernel cache flushing code so that writes would only be flushed to disk every 30 minutes or so. My laptop was plenty reliable, and it would always do a sync before I’d close the lid anyway, so that saved on the disk usage. But these days, I’m not so sure how to do that, with either ext3 or reiser4. Any suggestions?

As I mentioned earlier, I purchased an HP tc1100 tablet PC. It arrived earlier this week and I’ve been playing with it. Here are some of my initial impressions:

Debian stable (sarge) installed easily. The tc1100 has no optical drive, and I have no USB optical drive either. It also wouldn’t boot from a CF card in my USB card reader. So I did a PXE (network) boot. I had never known that Debian’s installer can boot over the network. VERY slick work, d-i team. During the installation, I noticed letter “Q” appearing on-screen periodically. I eventually determined that it would happen whenever I’d bump one of the mouse buttons. It also went away once I was using my own kernel, for whatever reason. The basic install was easy, no troubles at all. I was particularly impressed with the integration of ntfsresize these days. Being able to shrink down the XP partition to a very small size and then install Linux — very nice indeed.

There are lots of pages about the tc1100 under Linux, so I won’t rehash them all here. There are a few patches to the kernel to enable wireless support and the touchpad. All fairly straightforward. My unit uses the ipw2200 instead of the ipw2100 that everyone else seems to have, strangely enough.

The main thing I don’t have yet is suspend-to-memory (ACPI state S3). Standby (ACPI state S1) doesn’t have any noticable effect. With S3, the system will suspend, but crash on recovery. Can’t quite figure it out.

I did get hibernate (suspend-to-disk) working. I just have to shut down PCMCIA and unload the b44 Ethernet driver before engaging it, and then it’ll work fine. Not as nice as a true suspend, but still better than powering down all the time.

As far as apps go, the one that I really must mention so far is Jarnal. It’s an awesome program. At its simplest, it’s just a set of pages you can draw on on-screen. But there’s a lot more to it under the hood. First, it saves your work as a zipped set of SVG files, one per page. So you can load up your drawings into other programs later. Secondly, you can load up PDF files as the background, effectively letting you mark up documents and jot notes on them. Finally, there is a collaborative network mode that I haven’t even tried yet. Jarnal is GPL’d, but it requires Java 1.4.x. If if weren’t for that, I’d be uploading it to sid in a heartbeat.

I’ll keep posting as I have more thoughts.

Thanks to the advice both from comments here, and from e-mails I’ve received (thanks!), I’ve ordered a HP tc1100 tablet. Woohoo.

I do hope that the Linux ACPI support for it is ironed out by the time it arrives :-)