linux-kernel - Re: Possible issue with dangling PCI BARs

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Date:	Thu, 13 Dec 2007 14:04:58 +1100
From:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:	linux-pci@...ey.karlin.mff.cuni.cz
Cc:	Linux Kernel list <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: Possible issue with dangling PCI BARs

On Thu, 2007-12-13 at 14:00 +1100, Benjamin Herrenschmidt wrote:

 .../...

(oops, sent too fast)

> So not only we can have a dangling BAR, but nothing prevent us to
> actually go turn IO or MEM decoding on in case it wasn't already the
> case on that device.

And I was about to say before I clicked "send".. can't we do something like
writing all ff's into the BAR at the same time as we clear res->start ? Isn't
that supposed to pretty much disable decoding on that BAR ? Or not... Probably
still better than leaving it to whatever dangling value it had no ?

Also, maybe we should disable IO and MEM decoding by default on devices for
which one resource of that type failed to allocate ?

Ben.

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