From: "David S. Miller" <davem@davemloft.net>
To: rdreier@cisco.com
Cc: benh@kernel.crashing.org, linux-kernel@vger.kernel.org,
linux-pci@atrey.karlin.mff.cuni.cz
Subject: Re: MSI and driver APIs
Date: Thu, 15 Dec 2005 13:42:16 -0800 (PST) [thread overview]
Message-ID: <20051215.134216.18400210.davem@davemloft.net> (raw)
In-Reply-To: <adaek4enjoz.fsf@cisco.com>
From: Roland Dreier <rdreier@cisco.com>
Date: Thu, 15 Dec 2005 13:18:04 -0800
> Benjamin> I'm tempted to leave them enabled and only disable them
> Benjamin> when request_irq() is done on the legacy INTx... Does
> Benjamin> anybody see a problem with this approach ?
>
> You might run into trouble on hardware (think tg3 or its ilk again)
> where you might have to do something beyond disabling MSI in the PCI
> header to switch the chip out of MSI mode.
I think because of kinds of cases and other issues, going with
MSI by default is a non-starter.
Perhaps a better approach is to use a flag in the pci_driver_struct or
similar that says "you can have MSI enabled by default". And
gradually convert drivers over which we know will handle it properly.
Doing some tom foolery with request_irq() sounds like a half-baked
idea at best. The biggest argument against that is that this is
not a PCI interface, so expecting it to have PCI side effects is
really asking for trouble.
next prev parent reply other threads:[~2005-12-15 21:43 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-12-15 3:38 Benjamin Herrenschmidt
2005-12-15 21:07 ` Roland Dreier
2005-12-15 21:08 ` Benjamin Herrenschmidt
2005-12-15 21:18 ` Roland Dreier
2005-12-15 21:18 ` Benjamin Herrenschmidt
2005-12-15 21:36 ` Roland Dreier
2005-12-15 21:42 ` David S. Miller [this message]
2005-12-15 21:56 ` Benjamin Herrenschmidt
2005-12-16 0:51 ` Greg KH
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