From: Yinghai Lu <yinghai@kernel.org>
To: Grant Grundler <grundler@parisc-linux.org>
Cc: Alex Williamson <alex.williamson@hp.com>,
jbarnes@virtuousgeek.org, linux-pci@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] PCI: Always set prefetchable base/limit upper32 registers
Date: Tue, 01 Dec 2009 13:14:08 -0800 [thread overview]
Message-ID: <4B158720.9030008@kernel.org> (raw)
In-Reply-To: <20091201205910.GB16534@lackof.org>
Grant Grundler wrote:
> On Tue, Dec 01, 2009 at 12:40:03PM -0800, Yinghai Lu wrote:
> ...
>>> I assumed Yinghai's objection was based on a specific problem he had
>>> seen with writing upper32 register. Bjorn asked the right question.
>>> If there isn't a specific problem, I'd prefer AW's simpler patch.
>> we just should not touch that register if the HW only support 32bit pref mmio.
>
> Why not?
>
> I agree the PCI-PCI spec defines how to determine if a PCI Bridge supports
> 64-bit Pref MMIO (using upper32 - or not). But spec also doesn't prohibit
> writing to a read-only register. Writing this Read-Only register so far
> hasn't caused any problems.
if we can find out that is 32bit mmio pref, why waste cycle to write value to them?
YH
next prev parent reply other threads:[~2009-12-01 21:15 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-30 21:51 [PATCH v2] PCI: Always set prefetchable base/limit upper32 registers Alex Williamson
2009-12-01 0:03 ` Grant Grundler
2009-12-01 0:19 ` Grant Grundler
2009-12-01 1:23 ` Yinghai Lu
2009-12-01 4:10 ` Alex Williamson
2009-12-01 19:55 ` Grant Grundler
2009-12-01 20:40 ` Yinghai Lu
2009-12-01 20:59 ` Grant Grundler
2009-12-01 21:14 ` Yinghai Lu [this message]
2009-12-05 0:01 ` Jesse Barnes
2009-12-05 14:49 ` Alex Williamson
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