From: Oliver Neukum <oliver@neukum.org>
To: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Witold Szczeponik <Witold.Szczeponik@gmx.net>,
linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org,
Bjorn Helgaas <bjorn.helgaas@hp.com>, Adam Belay <abelay@mit.edu>,
rjw@sisk.pl
Subject: Re: [PATCH] PNPACPI: Enable Power Support
Date: Wed, 10 Dec 2008 11:22:59 +0100 [thread overview]
Message-ID: <200812101123.00055.oliver@neukum.org> (raw)
In-Reply-To: <20081210095315.GA20627@khazad-dum.debian.net>
Am Mittwoch, 10. Dezember 2008 10:53:15 schrieb Henrique de Moraes Holschuh:
> Although I do wonder WTF we don't do that on our USB UHCI/EHCI kernel
> drivers, that ACPI needs to step in to fix it. If it is not a wake
EHCI/UHCI have no way to power down host controllers.
It needs external means, namely ACPI.
> device, why are we leaving it powered up? It is bad enough we don't
> have any sort of proper USB power control, but to leave the entire USB
> subsystem powered up without reason?!
We don't. If you unplug all devices, USB will power down as much as is
compatible with detecting new devices.
> Vista not only powers down the USB HCIs and ports on STR, it also
> powers down ports when you "safely remove the USB device", and seems
> to leave the port powered down until you insert a device (or remove
> the device already in there, whatever).
If you cut power to a port, you cannot detect a hotplugging. You can
suspend it, which Linux does do.
Regards
Oliver
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next prev parent reply other threads:[~2008-12-10 10:21 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-08 20:57 [PATCH] PNPACPI: Enable Power Support Witold Szczeponik
2008-12-09 2:49 ` Adam M Belay
2008-12-09 3:00 ` Bjorn Helgaas
2008-12-09 3:25 ` Adam M Belay
2008-12-10 19:32 ` Witold Szczeponik
2008-12-10 9:53 ` Henrique de Moraes Holschuh
2008-12-10 10:22 ` Oliver Neukum [this message]
2008-12-10 23:26 ` Henrique de Moraes Holschuh
2008-12-10 19:30 ` Witold Szczeponik
2008-12-10 23:21 ` Henrique de Moraes Holschuh
2008-12-11 1:28 ` Henrique de Moraes Holschuh
2008-12-11 1:50 ` Henrique de Moraes Holschuh
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