From: Thomas Gleixner <tglx@linutronix.de>
To: Andres Salomon <dilinger@queued.net>
Cc: Jens Rottmann <JRottmann@LiPPERTEmbedded.de>,
linux-kernel@vger.kernel.org, linux-geode@lists.infradead.org
Subject: Re: IRQF_TIMER | IRQF_SHARED ?
Date: Tue, 13 Dec 2011 00:38:44 +0100 (CET) [thread overview]
Message-ID: <alpine.LFD.2.02.1112130035550.3020@ionos> (raw)
In-Reply-To: <20111212123131.502be350@queued.net>
On Mon, 12 Dec 2011, Andres Salomon wrote:
> On Mon, 12 Dec 2011 16:41:25 +0100
> Jens Rottmann <JRottmann@LiPPERTEmbedded.de> wrote:
>
> > But I did not fail to notice that _none_ of the code in
> > drivers/clocksource/ uses IRQF_SHARED, obviously this must be
> > deliberate.
>
> Hm, maybe tglx knows? For my part, I don't think it would be a
> problem, but I can imagine the reason for not sharing being clock drift
> or something to that effect.
No, you can share a timer irq. The other drivers don't have the SHARED
flag set because they are on exclusive irq lines, which is the sane
thing to do. shared irqs suck and you figure that out once you try to
use that shared timer irq on a preempt-rt enabled kernel.
Thanks,
tglx
next prev parent reply other threads:[~2011-12-12 23:38 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-12 15:41 Jens Rottmann
2011-12-12 20:31 ` Andres Salomon
2011-12-12 21:00 ` Martin-Éric Racine
2011-12-12 22:06 ` Andres Salomon
2011-12-12 23:38 ` Thomas Gleixner [this message]
2011-12-13 15:49 ` Jens Rottmann
2011-12-14 18:37 ` Jens Rottmann
2011-12-14 18:47 ` Andres Salomon
2011-12-21 15:42 ` [PATCH] cs5535-clockevt: don't ignore MFGPT on SMP-capable kernels Jens Rottmann
2012-01-11 10:10 ` Andres Salomon
2012-01-19 12:57 ` Jens Rottmann
2012-01-23 10:44 ` Andres Salomon
2011-12-21 16:37 ` IRQF_TIMER | IRQF_SHARED ? Jens Rottmann
2011-12-22 16:35 ` [PATCH] cs5535-clockevt: allow the MFGPT IRQ to be shared Jens Rottmann
2012-01-11 10:15 ` Andres Salomon
2012-01-30 13:51 ` [PATCH] cs5535-clockevt: don't ignore MFGPT on SMP-capable kernels Jens Rottmann
2012-01-30 13:59 ` [PATCH] cs5535-clockevt: allow the MFGPT IRQ to be shared Jens Rottmann
2012-02-06 8:20 ` [PATCH resend] cs5535-clockevt: don't ignore MFGPT on SMP-capable kernels Jens Rottmann
2012-02-06 8:23 ` [PATCH resend] cs5535-clockevt: allow the MFGPT IRQ to be shared Jens Rottmann
2011-12-19 14:32 ` "clockevents: Set noop handler in clockevents_exchange_device()" causes hang with cs5535-clockevt Jens Rottmann
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