Hi,
On 14-11-17 15:49, Justin Forbes wrote:
On Mon, Nov 13, 2017 at 10:16 AM, Chris Murphy <lists@xxxxxxxxxxxxxxxxx> wrote:
On Mon, Nov 13, 2017 at 8:40 AM, Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
Hi all,
As mentioned before I'm working on trying to improve the OOTB
power-consumption of Fedora Workstation on laptops
(I need to create an F28 feature page for this).
On many laptops the btusb device is the only USB device not
having USB autosuspend enabled, this causes not only the btusb
device but also the USB controller to stay awake, together using
aprox. 0.4W of power. Modern ultrabooks idle around 6W
(at 50% screen brightness), 3.5W for Apollo Lake devices.
0.4W is a significant chunk of this (7 / 11%).
So I would like to enable btusb autosuspend by default, to
make this possible I've submitted the following kernel
patch upstream which has just been merged (queued for 4.16):
https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git/commit/?id=86be3c232877b59f08561b256ff7e73ad39b0785
If it is ok with the Fedora kernel team I would like to add
this as a patch to the Fedora kernels for now and set
the new BT_HCIBTUSB_AUTOSUSPEND option to y. This is not
without a risk of regressions, so this is something for
rawhide/F28 only.
This is really useful work. I'm already seeing ~20% battery
improvement with Fedora 27 + 4.14.0-0.rc8.git3.1.fc28.x86_64 on an HP
Spectre, and so far no regressions. I get better battery life with
this combination than running Windows 10 with all the HP specific
drivers for this model.
Some tips on how regressions might manifest and what information to
include in a good bug report would be useful. e.g. on an Intel NUC
when I run powertop --auto-tune, and walk away (it's a server so it
might be days) and come back the keyboard won't work. I've never done
any troubleshooting other than just disable the powertop systemd unit,
I'm vaguely suspicious of usb autosuspend and it not waking up when
keys are pressed.
Auto suspend can be a real problem when it is keyboards and mice. I
know there was a huge uproar with logitech unified receiver users when
powertop would change the receiver to autosuspend and the
keyboard/mouse became unresponsive for a couple of key presses. To be
honest, I think this particular change may do much more harm than
good.
This is NOT about enabling USB autosuspend everywhere, only for USB
connected bluetooth receivers. The problems with mice and keyboards
and USB autosuspend are well known and I've no intention to enable
USB autosuspend for those.
Regards,
Hans
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