From: Tejun Heo <htejun@gmail.com>
To: Matthew Wilcox <matthew@wil.cx>
Cc: Arjan van de Ven <arjan@infradead.org>,
linux-pci@atrey.karlin.mff.cuni.cz, Greg KH <greg@kroah.com>,
lkml <linux-kernel@vger.kernel.org>
Subject: Re: question regarding cacheline size
Date: Thu, 07 Sep 2006 14:53:57 +0200 [thread overview]
Message-ID: <45001665.9050509@gmail.com> (raw)
In-Reply-To: <20060907124026.GN2558@parisc-linux.org>
Matthew Wilcox wrote:
> On Thu, Sep 07, 2006 at 02:33:25PM +0200, Arjan van de Ven wrote:
>>> So I think we should redo the PCI subsystem to set cacheline size during
>>> the buswalk rather than waiting for drivers to ask for it to be set.
>> ... while allowing for quirks for devices that go puke when this
>> register gets written ;)
>>
>> (afaik there are a few)
>
> So you want:
>
> unsigned int no_cls:1; /* Device pukes on write to Cacheline Size */
>
> in struct pci_dev?
The spec says that devices can put additional restriction on supported
cacheline size (IIRC, the example was something like power of two >= or
<= certain size) and should ignore (treat as zero) if unsupported value
is written. So, there might be need for more low level driver
involvement which knows device restrictions, but I don't know whether
such devices exist.
--
tejun
next prev parent reply other threads:[~2006-09-07 12:54 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-09-07 8:31 question regarding cacheline size Tejun Heo
2006-09-07 11:11 ` Matthew Wilcox
2006-09-07 11:20 ` Tejun Heo
2006-09-07 12:07 ` Russell King
2006-09-07 12:23 ` Matthew Wilcox
2006-09-07 12:33 ` Arjan van de Ven
2006-09-07 12:40 ` Matthew Wilcox
2006-09-07 12:53 ` Tejun Heo [this message]
2006-09-07 13:04 ` Matthew Wilcox
2006-09-07 13:19 ` Tejun Heo
2006-09-07 15:21 ` Grant Grundler
2006-09-07 15:47 ` Tejun Heo
2006-09-07 16:00 ` Jeff Garzik
2006-09-07 17:00 ` Matthew Wilcox
2006-09-07 16:04 ` Jeff Garzik
2006-09-22 23:47 ` Grant Grundler
2006-09-07 13:30 ` Jeff Garzik
2006-09-07 13:10 ` Russell King
2006-09-07 13:01 ` Arjan van de Ven
2006-09-07 13:02 ` Russell King
2006-09-07 11:59 ` linux-os (Dick Johnson)
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