From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Jeff Garzik <jgarzik@pobox.com>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
"Ingo Molnar" <mingo@elte.hu>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Björn Steinbrink" <B.Steinbrink@gmx.de>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: 2.6.24-git: kmap_atomic() WARN_ON()
Date: Wed, 27 Feb 2008 00:02:22 +0000 [thread overview]
Message-ID: <20080227000222.158f9220@core> (raw)
In-Reply-To: <47C499CF.2000605@pobox.com>
> Aside: The "FIXME: use bounce buffer" comment above indicates the more
> optimal PIO data xfer approach of
>
> local_irq_save()
> kmap_atomic()
> memcpy into bounce buffer
> kunmap_atomic()
> local_irq_restore()
>
> /* do slow PIO bitbanging data transfer */
> ap->ops->data_xfer(...)
Definitely - older PATA controllers are unbuffered. A PIO_0 transfer is
running at ISA speed with IRQs off. Guaranteed to give Ingo's RT a blip.
Alan
next prev parent reply other threads:[~2008-02-27 0:15 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-06 23:58 2.6.24-git: kmap_atomic() WARN_ON() Thomas Gleixner
2008-02-13 22:39 ` Rafael J. Wysocki
2008-02-14 1:13 ` Thomas Gleixner
2008-02-25 19:59 ` Björn Steinbrink
2008-02-25 20:08 ` Jeff Garzik
2008-02-25 20:35 ` Björn Steinbrink
2008-02-25 20:40 ` Andrew Morton
2008-02-25 22:01 ` Thomas Gleixner
2008-02-25 22:17 ` Andrew Morton
2008-02-25 23:19 ` Jeff Garzik
2008-02-26 8:39 ` Ingo Molnar
2008-02-26 16:32 ` Jeff Garzik
2008-02-26 18:19 ` Andrew Morton
2008-02-26 20:49 ` Ingo Molnar
2008-02-26 21:37 ` Andrew Morton
2008-02-26 22:59 ` Jeff Garzik
2008-02-27 0:02 ` Alan Cox [this message]
2008-02-26 23:49 ` Nick Piggin
2008-02-26 8:50 ` Thomas Gleixner
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