I post this after a few days of wrestling with my brand new Acer TravelMate 401WLMi. Its a fantastic laptop and i have come across only one problem thus far with it, and that is the battery monitor in linux. I have tried the stock 2.6.15 kernel, the archck series, and a few that i have compiled myself and none have seemed to get me any acknowledgement that there is a battery in the system. Dmesg gives me lots of acpi errors on bootup, but everything works but the battery. Having researched the topic, it seems that the battery is a "smartbattery" and uses the smb bus to send/recieve battery information. I attempted patching my kernel using this
but the patch to my dsdt didnt go smoothly.it ended up that by applying the patch i was able to create to my initrd, I actually killed support for my onboard wifi card, so i figured that wasnt the way to go. I wondered if anyone has any more ideas or any stories of getting the battery sensors to work properly on an acer laptop.
Just as a side note, i threw in a Kanotix live cd and it picks it up fine, but all i can find about the kanotix kernel is that its compiled with "a lot of patches." i imagine if i could find what patches they applied, i could get to the root of my problem, but again i havent been able to find any information regarding that.
got it working today in another painful day of kernel compiling. turns out that in order to properly detect my battery i had to compile ACPI battery as a module and explicitly load it via the array in rc.conf. i never did feel like tpowa's hwdetect loaded everything flawlessly but i never mind a good bit of tinkering in good fun when i get a chance i'll add this laptop to the wiki and hopefully to tuxmobil.. this laptop is a great buy in case anyone is looking, but linux documentation is definately sparse.
ok well with further tinkering i found that forcing the module would create BAT0 in /proc/acpi/battery. i usually run without the battery in the laptop because i'm weird like that.. and i forgot i didnt have anything in there. when i polled the battery, it said none present so i shut down, installed the battery, and booted back up. this time, the module was seen as being used in lsmod, but BAT0 dissapeared in /proc/acpi/battery. i am utterly confused. upon trying the kanotix live cd, as well as numerous other live cd's, nothing picks up the battery or even sees anything in /proc/acpi/battery so i dont know where to go from here. anyone have any ideas?