brcmsmac wireless driver does not have power management enabled and is eating batteries
A lot of people have been reporting that the oneiric kernels have been sucking up power (which they were, early on), but a closer look shows that the kernel regressions are mainly all fixed - however, the brcmsmac wireless driver appears to be a main culprit left, sucking up to ~3W of power.
As far as I can tell, the use of the brcmsmac wireless driver co-incided with the use of the introduction of the kernel bug that was making battery life poor for many oneiric users, and I suspect that this is one of the major contributors to that problem. Perhaps the brcmsmac should be rolled back until power management is available, or a push on this driver could possibly enable this feature. Either one would be a good way to extend battery life for laptop users.
I am using: Ubuntu 3.0.0-12.19-generic 3.0.4 (Oneiric, with up to date packages)
The important line from lspci is:
03:00.0 Network controller : Broadcom Corporation BCM43224 802.11a/b/g/n [14e4:4353] (rev 01)
Subsystem: Apple Computer Inc. Device [106b:0093]
Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Latency: 0, Cache Line Size: 256 bytes
Interrupt: pin A routed to IRQ 17
Region 0: Memory at c1b00000 (64-bit, non-prefetchable) [size=16K]
Kernel driver in use: brcmsmac
Kernel modules: wl, bcma, brcmsmac
The battery reports a discharge rate of 16.6 W
Summary: 0.0 wakeups/second, 0.0 GPU ops/second and 0.0 VFS ops/sec
Power est. Usage Events/s Category Description
2.61 W 100.0% Device Radio device: brcmsmac
2.35 W 60.0% Device Display backlight
759 mW 29.5 ms/s 0.0 Process /usr/sbin/
727 mW 20.5% Device Audio codec alsa:hwC0D0: mbp55 (Cirrus Logic)
564 mW 40.7 pkts/s Device Network interface: wlan0 (brcmsmac)
469 mW 18.3 ms/s 0.0 Process /usr/bin/knotify4
279 mW 10.9 ms/s 0.0 Process /usr/lib/
260 mW 10.1 ms/s 0.0 Process powertop
and, of course some output from iwconfig:
wlan0 IEEE 802.11abgn ESSID:"XXXXXXXXXX"
Bit Rate=54 Mb/s Tx-Power=19 dBm
Retry long limit:7 RTS thr:off Fragment thr:off
Link Quality=47/70 Signal level=-63 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:15 Invalid misc:2221 Missed beacon:0
"sudo iwconfig wlan0 power on" gives:
Error for wireless request "Set Power Management" (8B2C) :
SET failed on device wlan0 ; Operation not supported.
What I expected:
Ubuntu would not use a wireless driver on laptops that eats 3W of power and can't be set to use less power.
My batteries are being drained by a wireless card that is constantly hot (I can feel it through the case) for which no option to enable power management exists.
|Changed in linux (Ubuntu):|
|status:||Incomplete → Confirmed|