From: Nix <nix@esperi.org.uk>
To: Damien Wyart <damien.wyart@free.fr>
Cc: Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
"H. Peter Anvin" <hpa@zytor.com>,
Artur Skawina <art.08.09@gmail.com>,
John Drescher <drescherjm@gmail.com>,
Venkatesh Pallipadi <venki@google.com>,
Arjan van de Ven <arjan@linux.intel.com>,
Andreas Herrmann <andreas.herrmann3@amd.com>,
Borislav Petkov <borislav.petkov@amd.com>,
Suresh Siddha <suresh.b.siddha@intel.com>
Subject: Re: [PATCH RFC] x86: hpet: Avoid the readback penalty
Date: Sat, 18 Sep 2010 14:43:06 +0100 [thread overview]
Message-ID: <87iq23i2vp.fsf@spindle.srvr.nix> (raw)
In-Reply-To: <20100918074939.GA3275@brouette> (Damien Wyart's message of "Sat, 18 Sep 2010 09:49:39 +0200")
On 18 Sep 2010, Damien Wyart uttered the following:
> * Thomas Gleixner <tglx@linutronix.de> [2010-09-15 15:11]:
>> > x86: hpet: Work around hardware stupidity
>
>> After my brain recovered from yesterdays exposure with the x86 timer
>> horror, I came up with a different solution for this problem, which
>> avoids the readback of the compare register completely. It works
>> nicely on my affected ATI system, but needs some exposure to the other
>> machines.
>
> Comments for this different solution seemed fine, but it seems only the
> first one was commited into mainline and then stable. Is this intended?
I assumed he was letting people shake the bugs out rather than inflict
what is basically just a performance improvement on -stable. For the
record: no bugs here. I also know why one of my machines was unaffected,
and it provides even more confirmation that this bug is correctly
identified, as if we needed more. It's not using the HPET at all:
Clock Event Device: cs5535-clockevt
Every single machine I owned with an HPET was affected by this bug: they
all work perfectly well now.
next prev parent reply other threads:[~2010-09-18 13:43 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <tip-54ff7e595d763d894104d421b103a89f7becf47c@git.kernel.org>
2010-09-14 23:36 ` [tip:x86/urgent] x86: hpet: Work around hardware stupidity Venkatesh Pallipadi
2010-09-15 13:11 ` [PATCH RFC] x86: hpet: Avoid the readback penalty Thomas Gleixner
2010-09-15 13:43 ` Anders Larsen
2010-09-15 13:54 ` John Drescher
[not found] ` <AANLkTikHfDUh3LdmyA5eMNACFPfi6pqGLFJiyzVm79X_@mail.gmail.com>
2010-09-16 4:45 ` Fwd: " John Drescher
2010-09-15 14:40 ` Borislav Petkov
2010-09-15 14:42 ` Thomas Gleixner
2010-09-16 12:28 ` Borislav Petkov
2010-09-16 20:04 ` Nix
2010-09-18 7:49 ` Damien Wyart
2010-09-18 9:41 ` Thomas Gleixner
2010-09-18 13:43 ` Nix [this message]
2010-09-18 10:13 ` [tip:x86/timers] x86: Hpet: Avoid the comparator " tip-bot for Thomas Gleixner
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