Hi Norbert, I have the exact same issue on a dell latitude e5510 running the x86_64 kernel. And on a dell latitude 1220 running the i686 kernel. Didn't know about the hack, thanks. Regards, Wim On Tue, May 17, 2011 at 7:26 PM, Norbert Zeh <nzeh@xxxxxxxxx> wrote: > Hi folks, > > I've run into a weird problem with monitoring the status of my laptop > battery. > Since I assume I'm doing something wrong, I thought I'd ask for feedback > here > first before going and filing a bug report. Here goes: > > When my machine boots, /sys/class/power_supply/BAT0 and all the files in it > do > not exist: > > $ ls /sys/class/power_supply > AC > > Since my battery monitor uses this as the source of information, it > obviously > fails. > > Now, as soon as I query the state of the battery through > /proc/acpi/battery/BAT0, the missing files under /sys/class/power_supply > get > created: > > $ cat /proc/acpi/battery/BAT0/state > present: yes > capacity state: ok > charging state: discharging > present rate: 1265 mA > remaining capacity: 4234 mAh > present voltage: 11340 mV > > $ ls /sys/class/power_supply > AC BAT0 > > This is not just a timeout issue. If I don't query > /proc/acpi/battery/BAT0/state, /sys/class/power_supply/BAT0 does not get > created even after a few hours of uptime. > > Also, after suspending, the files remain present but cannot be read. > Querying > the battery through the /proc interface once again brings everything back > to > normal. > > Now what's funny about this is that I read online that the > /proc/acpi/battery > interface is deprecated and that the /sys/... interface should be used > instead. > Yet, without querying the former, the latter doesn't even exist. > > Did anybody run into similar issues? Does anybody have any ideas how to > fix > this "the proper way"? (My workaround right now is to include "cat > /proc/acpi/battery/BAT0/state > /dev/null" in rc.local, but that's > obviously a > hack.) > > Thanks for any pointers you may give. > > Cheers, > Norbert > > PS: Machine is Dell Latitude E6510 running 64-bit ARCH. >
