Subject: Re: [Bulk] Re: [PATCH 1/2] [PCI] Check that MWI bit really did get
	set
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Andrew Morton <akpm@osdl.org>
Cc: Matthew Wilcox <matthew@wil.cx>, David Brownell <david-b@pacbell.net>,
       val_henson@linux.intel.com, netdev@vger.kernel.org,
       linux-pci@atrey.karlin.mff.cuni.cz, linux-kernel@vger.kernel.org,
       gregkh@suse.de
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Date: Sun, 15 Oct 2006 22:52:15 +0100
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Ar Sul, 2006-10-15 am 10:45 -0700, ysgrifennodd Andrew Morton:
> If the drivers doesn't care and if it makes no difference to performance
> then just delete the call to pci_set_mwi().
> 
> But if MWI _does_ make a difference to performance then we should tell
> someone that it isn't working rather than silently misbehaving?

It isn't misbehaving it just isn't available. MWI is rather different to
say pci_set_master() in that it makes a lot of sense for many drivers to
ask for it but not care about the results. Something like pci_set_master
failing is a big problem and has to be handled (although as we often
don't use BIOS PCI services we see fake success in some cases).

MWI is an "extra cheese" option not a "no pizza" case

Alan

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