1. 30 11月, 2012 2 次提交
  2. 28 11月, 2012 1 次提交
  3. 23 11月, 2012 1 次提交
  4. 22 11月, 2012 8 次提交
  5. 17 11月, 2012 1 次提交
    • K
      ACPI / battery: Correct battery capacity values on Thinkpads · 4000e626
      Kamil Iskra 提交于
      Add a quirk to correctly report battery capacity on 2010 and 2011
      Lenovo Thinkpad models.
      
      The affected models that I tested (x201, t410, t410s, and x220)
      exhibit a problem where, when battery capacity reporting unit is mAh,
      the values being reported are wrong.  Pre-2010 and 2012 models appear
      to always report in mWh and are thus unaffected.  Also, in mid-2012
      Lenovo issued a BIOS update for the 2011 models that fixes the issue
      (tested on x220 with a post-1.29 BIOS).  No such update is available
      for the 2010 models, so those still need this patch.
      
      Problem description: for some reason, the affected Thinkpads switch
      the reporting unit between mAh and mWh; generally, mAh is used when a
      laptop is plugged in and mWh when it's unplugged, although a
      suspend/resume or rmmod/modprobe is needed for the switch to take
      effect.  The values reported in mAh are *always* wrong.  This does
      not appear to be a kernel regression; I believe that the values were
      never reported correctly.  I tested back to kernel 2.6.34, with
      multiple machines and BIOS versions.
      
      Simply plugging a laptop into mains before turning it on is enough to
      reproduce the problem.  Here's a sample /proc/acpi/battery/BAT0/info
      from Thinkpad x220 (before a BIOS update) with a 4-cell battery:
      
      present:                 yes
      design capacity:         2886 mAh
      last full capacity:      2909 mAh
      battery technology:      rechargeable
      design voltage:          14800 mV
      design capacity warning: 145 mAh
      design capacity low:     13 mAh
      cycle count:              0
      capacity granularity 1:  1 mAh
      capacity granularity 2:  1 mAh
      model number:            42T4899
      serial number:           21064
      battery type:            LION
      OEM info:                SANYO
      
      Once the laptop switches the unit to mWh (unplug from mains, suspend,
      resume), the output changes to:
      
      present:                 yes
      design capacity:         28860 mWh
      last full capacity:      29090 mWh
      battery technology:      rechargeable
      design voltage:          14800 mV
      design capacity warning: 1454 mWh
      design capacity low:     200 mWh
      cycle count:              0
      capacity granularity 1:  1 mWh
      capacity granularity 2:  1 mWh
      model number:            42T4899
      serial number:           21064
      battery type:            LION
      OEM info:                SANYO
      
      Can you see how the values for "design capacity", etc., differ by a
      factor of 10 instead of 14.8 (the design voltage of this battery)?
      On the battery itself it says: 14.8V, 1.95Ah, 29Wh, so clearly the
      values reported in mWh are correct and the ones in mAh are not.
      
      My guess is that this problem has been around ever since those
      machines were released, but because the most common Thinkpad
      batteries are rated at 10.8V, the error (8%) is small enough that it
      simply hasn't been noticed or at least nobody could be bothered to
      look into it.
      
      My patch works around the problem by adjusting the incorrectly
      reported mAh values by "10000 / design_voltage".  The patch also has
      code to figure out if it should be activated or not.  It only
      activates on Lenovo Thinkpads, only when the unit is mAh, and, as an
      extra precaution, only when the battery capacity reported through
      ACPI does not match what is reported through DMI (I've never
      encountered a machine where the first two conditions would be true
      but the last would not, but better safe than sorry).
      
      I've been using this patch for close to a year on several systems
      without any problems.
      
      References: https://bugzilla.kernel.org/show_bug.cgi?id=41062Acked-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      4000e626
  6. 16 11月, 2012 8 次提交
  7. 15 11月, 2012 19 次提交