linux-kernel - Re: CONFIG_PCIEASPM needed for ASPM?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 24 Oct 2008 10:47:47 +0800
From:	Shaohua Li <shaohua.li@...el.com>
To:	"Luis R. Rodriguez" <mcgrof@...il.com>
Cc:	"Zhang, Yanmin" <yanmin.zhang@...el.com>,
	Linux-Kernel <linux-kernel@...r.kernel.org>
Subject: Re: CONFIG_PCIEASPM needed for ASPM?

On Fri, Oct 24, 2008 at 09:40:27AM +0800, Luis R. Rodriguez wrote:
> I know, the question is silly right? I thought so too, but I started
> reviewing the code and noticed most of it is just setting up values in
> data structures for the kernel's awareness of capabilities, it also
> updates the state in case of BIOS foobar, and there is also clock
> retraining if possible to reduce latency. Is that it? Did I miss
> something or is it really possible for devices to be able to use
> L0s|L1 or L1 by just having a BIOS which does things correctly?
> 
> That is can our devices be using ASPM without any OS interaction,
> without CONFIG_PCIEASPM enabled?
you didn't miss anything. If BIOS enables ASPM, even OS doesn't do anything,
ASPM will be used. ASPM enter/leave is controlled by hardware, OS just
enables the capability.

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