linux-kernel - Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override

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]

Message-ID: <20071231131107.GA26339@ucw.cz>
Date:	Mon, 31 Dec 2007 13:11:12 +0000
From:	Pavel Machek <pavel@....cz>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Alan Cox <alan@...rguk.ukuu.org.uk>,
	Rene Herman <rene.herman@...access.nl>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	dpreed@...d.com, Islam Amer <pharon@...il.com>, hpa@...or.com,
	Ingo Molnar <mingo@...hat.com>,
	Andi Kleen <andi@...stfloor.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override

On Sun 2007-12-30 21:46:50, Ingo Molnar wrote:
> 
> * Alan Cox <alan@...rguk.ukuu.org.uk> wrote:
> 
> > > So the current plan is to go with an io_delay=udelay default in v2.6.25, 
> > > to give this a migration window, and io_delay=none in v2.6.26 [and a 
> > > complete removal of arch/x86/kernel/io_delay.c], once the _p() uses are 
> > > fixed up. This is gradual enough to notice any regressions we care about 
> > > and also makes it nicely bisectable and gradual.
> > 
> > You will break systems if you blindly go around disabling _p delays 
> > for ISA and LPC bus devices. The DEC Hinote laptops for example are 
> > well known for requiring the correct ISA and other keyboard controller 
> > delays. I don't expect anyone to test with a hinote or see it until it 
> > hits Debian or similar 'low resource' friendly devices.
> 
> well, using io_delay=udelay is not 'blindly disabling'. io_delay=none 
> would be the end goal, once all _p() API uses are eliminated by 
> transformation. In drivers/ alone that's more than 1000 callsites, so 
> it's quite frequently used, and wont go away overnight.

IOW elimination of broken inb_p()/outb_p() interfaces is the ultimate
goal. Agreed.

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
--
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/