linux-kernel - Re: [PATCH] Blacklist Dell Optiplex 320 from using the HPET

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:	Sat, 05 May 2007 21:15:01 +0200
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Andi Kleen <ak@...e.de>
Cc:	john stultz <johnstul@...ibm.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Guilherme M. Schroeder" <guilherme@...tralinf.com.br>,
	lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] Blacklist Dell Optiplex 320 from using the HPET

On Sat, 2007-05-05 at 19:24 +0200, Andi Kleen wrote:
> >  	if (!is_hpet_capable())
> > @@ -278,6 +279,14 @@ int __init hpet_enable(void)
> >  	/* Start the counter */
> >  	hpet_start_counter();
> >  
> > +	/* Verify whether hpet counter works */
> > +	t1 = hpet_read();
> > +	udelay(50);
> 
> Are you sure udelay is calibrated at this point? I didn't think so.
> In fact it needs the external clocks and it's a chicken and egg problem.

Oops. You are right. OTOH it does not matter whether it is accurate or
not.

> It might be safer to use a long loop with io port accesses or similar.

Should work as well.

	tglx


-
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/