T420 battery threshold doesn't work

[chx]

echo 40 > /sys/devices/platform/smapi/BAT0/start_charge_thresh
[117661.051803] smapi smapi: smapi_request: SMAPI error: SMAPI function is not available (func=2116)
[117661.051815] smapi smapi: __get_real_thresh: cannot get start_thresh of bat=0: SMAPI function is not available

[chx]

This is essentially a duplicate of http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=628829

[evgeni]

No it's not.
T420 only supports stop, not start. Bark at Lenovo for breaking the interface :)
Does https://gitorious.org/linux-test-utils/tp_charge work for start and stop for you?

[chx]

I didnt even https://gitorious.org/linux-test-utils/tp_charge/blobs/master/tp_charge.c#line18 try.

[evgeni]

Would you please try? :)

[chx]

OK I tried:

Request IO permissions.
Get BAT0 start.
get_threshold: Function not implemented
Get BAT0 stop.
start = 255, stop = 0

[mluessi]

I have a T420s with the same problem. Is there a way to get the addresses needed for setting/getting the thresholds from the Lenovo Windows utility?

[evgeni]

reverse engeneer it :)
i currently have no docs/ideas how to fix it :/

[teleshoes]

hello!
there are ACPI calls for this that work on my W520. {start/stop threshold, inhibit charge, and force-discharge-on-ac-only}. see if my perl script works for any of you:
https://github.com/teleshoes/tpbattstat-applet/blob/master/tpacpi-bat

[teleshoes]

it requires that you install acpi_call kernel module
e.g.:
git clone git://github.com/mkottman/acpi_call.git acpi_call
cd acpi_call
make
sudo insmod acpi_call.ko

[chx]

[root@veyron2 acpi_call-git]# perl /tmp/tpacpi-bat.pl startChargeThreshold 0 40
Calling : _SB.PCI0.LPC.EC.HKEY.BCCS 0x28
Response: 0x0

Does that mean it worked? I am on a T420.

[teleshoes]

damn that was fast. it means that the ACPI interface responded with a 0, which is a very good sign but not a perfect confirmation.
try forceDischarge with the AC adapter connected and see if it starts discharging.

[chx]

[root@veyron2 acpi_call-git]# perl /tmp/tpacpi-bat.pl forceDischarge 1 1
Calling : _SB.PCI0.LPC.EC.HKEY.BDSS 0x101
Response: 0x0
[root@veyron2 acpi_call-git]# cat /sys/class/power_supply/BAT0/status
Discharging

Looks good.

[teleshoes]

so then, yes, it means its working. im a little confused, though, about why tee isnt printing the backslash.
when i run the same thing, i get:

teleshoes:~/tpbattstat-applet$ sudo ./tpacpi-bat forceDischarge 1 1
Calling : _SB.PCI0.LPC.EC.HKEY.BDSS 0x101
Response: 0x0

[chx]

Let me link http://www.thinkwiki.org/wiki/Maintenance#Battery_treatment this for people coming around later. You want approx 30-85 for your discharge thresholds.

[chx]

teleshoes, what backslash, your output looks totally the same as mine?