Date: Wed, 19 Mar 2008 11:29:43 +0000 From: "Poul-Henning Kamp" <phk@phk.freebsd.dk> To: "M. Warner Losh" <imp@bsdimp.com> Cc: bzeeb-lists@lists.zabbadoz.net, arch@freebsd.org Subject: Re: Power-Mgt Message-ID: <8726.1205926183@critter.freebsd.dk> In-Reply-To: Your message of "Wed, 19 Mar 2008 05:16:04 CST." <20080319.051604.63052713.imp@bsdimp.com>
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In message <20080319.051604.63052713.imp@bsdimp.com>, "M. Warner Losh" writes:
>In message: <20080318085804.I50685@maildrop.int.zabbadoz.net>
> "Bjoern A. Zeeb" <bzeeb-lists@lists.zabbadoz.net> writes:
>: what actually happens to an unrecognized card or a card with no driver
>: loaded currently? How much power does an unsued card use and can we do
>: anything about that? Are we perhaps already doing something about
>: that?
>
>For PCI it is set into D3 state. Or at least was until this caused a
>problem with some raid controllers that didn't follow the rules and
>had extra devices that the card used, but that the OS didn't have a
>driver for.
>
>For PC Card, the card is powered down entirely. For CardBus I think
>the same. For USB, ugen takes it, and therefore it is powered up.
Not to mention this comment from acpi_cpu.c:
/*
* Check for bus master activity. If there was activity, clear
* the bit and use the lowest non-C3 state. Note that the USB
* driver polling for new devices keeps this bit set all the
* time if USB is loaded.
*/
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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