Power consumption on 802.11 / ASPM / device measurements

[Luis R. Rodriguez]

We've been accumulating a few power consumption related documents on
the wireless wiki for a while now. One which I saw was missing was for
actual power consumption and review of new PCI-E features which should
be taken into consideration when debugging power consumption or
reviewing it. ASPM is something that I can say I found little to no
documentation for when looking into it so I've done a brain dump of
what I recall from it, the code review of it, and some e-mail
exchanges I've had with Jonathan May @ Atheros.

I've stashed together all the power consumption docs at:

http://wireless.kernel.org/en/users/Documentation/Power-consumption

You'll see there some ASPM docs now and some ath9k specific power
consumption metrics/ASPM details. Please review and enhance as you see
fit.

Yanmin, Shaohua, I see CONFIG_PCIEASPM still marked as experimental,
I'm curious if this is still really that experimental and if there are
plans for it go out of experimental. Also I am little puzzled with
some of the aspm.c code, I see we fill the pci device struct with
capability stuff via pcie_aspm_cap_init() but I also see ASPM
capability stuff exposed on kernels without CONFIG_PCIEASPM (albeit I
see it always disabled on my system at home), so are we filling the
capability elsewhere? I think there are some boxes without this kernel
config enabled and where ASPM capability info is exposed and does show
up as enabled, could be wrong.

Also curious -- how often are BIOSes buggy enough for ASPM to get
disabled by mistake on the modern devices? And for systems that have
no Bios (*cough* ChromeOS) how is this handled?

 Luis
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/