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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Yinghai Lu <yinghai@kernel.org>
Cc: "Bjorn Helgaas" <bhelgaas@google.com>,
	"Gavin Shan" <gwshan@linux.vnet.ibm.com>,
	"Marek Kordík" <kordikmarek@gmail.com>,
	zermond@gmail.com, linux-pci@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] PCI: Clear bridge MEM_64 flag if one child does not support it
Date: Tue, 09 Dec 2014 09:56:12 +1100	[thread overview]
Message-ID: <1418079372.13358.9.camel@kernel.crashing.org> (raw)
In-Reply-To: <1418075552-26495-1-git-send-email-yinghai@kernel.org>

On Mon, 2014-12-08 at 13:52 -0800, Yinghai Lu wrote:
> 2. or scan the children resource other than ROM to clear bridge MEM_64
>    for mmio pref.
> 
> The patch is using second way so will keep child mmio pref into bridge
> mmio pref range.

That means that having a single ROM BAR that is 32-bit and prefetchable
will downgrade the entire window to 32-bit ? That's not going to work
either.

I have GPUs with 16G BARs for example... suddenly they don't fit
anaymore because we downgraded the window to 32 bit because somewhere
there's a 32-bit pref resource ?

That will break more than it fixes...

Ben.



  reply	other threads:[~2014-12-08 22:56 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-08 21:52 [PATCH] PCI: Clear bridge MEM_64 flag if one child does not support it Yinghai Lu
2014-12-08 22:56 ` Benjamin Herrenschmidt [this message]
2014-12-08 23:00   ` Benjamin Herrenschmidt
2014-12-09  0:09     ` Yinghai Lu
2014-12-09 21:39       ` Yinghai Lu
2014-12-08 23:59   ` Yinghai Lu
2014-12-09  0:11     ` Gavin Shan
2014-12-09  2:26       ` Wei Yang
2014-12-09  7:20         ` Yinghai Lu
2014-12-09  7:56           ` Wei Yang
2014-12-09 18:21             ` Bjorn Helgaas
2014-12-10  9:42               ` Wei Yang
2014-12-09 19:49             ` Yinghai Lu
2014-12-09 18:07           ` Marek Kordík
2014-12-09 18:22             ` Bjorn Helgaas
2014-12-09 19:42               ` Yinghai Lu
2014-12-09 22:15                 ` Marek Kordík
2014-12-09 23:16                   ` Yinghai Lu
2014-12-09  1:08     ` Gavin Shan
2014-12-09  1:38       ` Yinghai Lu

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