From: Grant <emailgrant@gmail.com>
To: Gentoo mailing list <gentoo-user@lists.gentoo.org>
Subject: Re: [gentoo-user] Powering down the USB controller
Date: Thu, 3 Jan 2013 21:24:21 -0800 [thread overview]
Message-ID: <CAN0CFw3ahfG-CUnc8DwvBt72F2PjunaM4=r5hi91dwXSxP25vA@mail.gmail.com> (raw)
In-Reply-To: <CAEH5T2MmK2w=zTsmGt+hmbLoe2QqM5Mb2heaS6rdAku+OnOPdg@mail.gmail.com>
>> I'm trying to get a USB sound card to behave in a certain way which
>> requires it to think the computer has gone to sleep. I'm told the
>> specific signal the sound card looks for is if the USB controller has
>> been physically powered down. Should I unload a kernel module to
>> accomplish this, or do I need to actually put the computer into sleep
>> mode?
>
> I don't think you can turn USB port off, at best you can suspend it,
> which is not truly 100% powered-down. I think you might be able to
> power off an entire hub (and never power it back on again until
> reboot) but I'm not sure if that will be any better than just
> unplugging the cable. You might be able to build some kind of simple
> USB on/off switch. :)
>
> Check out /sys/bus/usb/devices/[yourdevice]/power/level for current
> status and you can echo different commands to that same file to
> attempt to change its status. Check out the power management settings
> and documentation in the linux kernel for your options.
Will do, thanks Paul.
- Grant
prev parent reply other threads:[~2013-01-04 5:25 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-29 4:45 [gentoo-user] Powering down the USB controller Grant
2013-01-03 23:03 ` Paul Hartman
2013-01-04 5:24 ` Grant [this message]
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