From: Jeff Garzik <jgarzik@pobox.com>
To: Andrew Morton <akpm@osdl.org>
Cc: Dave Dillow <dave@thedillows.org>,
linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: Adaptec 1420SA issues with MSI
Date: Tue, 10 Jan 2006 01:31:16 -0500 [thread overview]
Message-ID: <43C354B4.2070505@pobox.com> (raw)
In-Reply-To: <20060109221323.65f6987d.akpm@osdl.org>
Andrew Morton wrote:
> Andi says "It's more likely a hardware bug that needs to be handled by the
> driver maintainer. sata_mv has an pci_enable_msi(). Hardware that reports
> MSI capability but breaks when it's actually used is not unheard of."
> It seems strange that pci_enable_msi() succeeded if the device is not
> MSI-capable?
Unfortunately this is not strange :( People have been coding interrupt
tests into MSI drivers -- shades of the early 90's -- because
pci_enable_msi() does not fail for systems that do not support MSI.
-Sometimes- it will fail as expected, if system does not support MSI,
sometimes not.
For this case -- 32bit non-Intel mobo chipset -- the cause of the
failure is likely the poor pci_enable_msi() test.
However, I know of at least one MSI-related sata_mv hardware bug that
needs working around, but that only affects 64-bit. Given that MSI
works with this chip on other systems, I'm leaning towards blaming the
system.
The following are reasonable workarounds:
* Add pci=nomsi kernel parameter... we really need this
* Add 'msi' module option to sata_mv
I'll try to get around to committing the errata to source code.
Marvell's triple-layered vendor driver is GPL'd, so anyone can steal
this task from me...
Jeff
next prev parent reply other threads:[~2006-01-10 6:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-07 21:06 Adaptec 1420SA issues with MSI Dave Dillow
2006-01-10 6:13 ` Andrew Morton
2006-01-10 6:31 ` Jeff Garzik [this message]
2006-01-17 19:39 ` Jeff Garzik
-- strict thread matches above, loose matches on Subject: below --
2006-01-07 4:53 Dave Dillow
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