linux-kernel - Re: [Bulk] Re: [PATCH 1/2] [PCI] Check that MWI bit really did get set

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Date:	Sun, 15 Oct 2006 07:52:51 -0600
From:	Matthew Wilcox <matthew@....cx>
To:	David Brownell <david-b@...bell.net>
Cc:	akpm@...l.org, val_henson@...ux.intel.com, netdev@...r.kernel.org,
	linux-pci@...ey.karlin.mff.cuni.cz, linux-kernel@...r.kernel.org,
	gregkh@...e.de
Subject: Re: [Bulk] Re: [PATCH 1/2] [PCI] Check that MWI bit really did get set

On Sun, Oct 15, 2006 at 12:08:09AM -0700, David Brownell wrote:
> > But the only effect of returning EINVAL is a printk (for this particular
> > driver):
> >
> >         /* PCI Memory-Write-Invalidate cycle support is optional (uncommon) */
> >         retval = pci_set_mwi(pdev);
> >         if (!retval)
> >                 ehci_dbg(ehci, "MWI active\n");
> 
> Erm, I've lost context here but it's completely legit for hardware
> to NOT support MWI, so it is in no way an error if it's not set.
> (Memory-Write-Invalidate is just a more efficient way to write data
> that may be cached; if the device can't issue those cycles, there's
> no loss of correctness.)
> 
> Since it's not an error, there should be no such printk ... which
> is exactly how it's coded above.
> 
> Who is issuing the printk on a non-error code path??

Er, that would be the EHCI driver, which you wrote ...
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