Enabling MSI in sata_nv

Enabling MSI in sata_nv

[Philip Langdale]

Hi all,

At least for my hardware (MCP55), the sata controller supports MSI
and it seems that turning it on is as simple as inserting the call
to pci_enable_msi - after that it Just Works(tm).

Are there any gotchas that I'm missing? Would a patch to do this
be accepted?

--phil

Re: Enabling MSI in sata_nv

[Mark Lord]

Philip Langdale wrote:
> Hi all,
> 
> At least for my hardware (MCP55), the sata controller supports MSI
> and it seems that turning it on is as simple as inserting the call
> to pci_enable_msi - after that it Just Works(tm).
> 
> Are there any gotchas that I'm missing? Would a patch to do this
> be accepted?
..

Don't even dream about it for now.  The driver is unstable enough
without throwing MSI into the works.

Maybe in the new year, once we get it more up to spec.

Cheers

Re: Enabling MSI in sata_nv

[Mark Lord]

Mark Lord wrote:
> Philip Langdale wrote:
>> Hi all,
>>
>> At least for my hardware (MCP55), the sata controller supports MSI
>> and it seems that turning it on is as simple as inserting the call
>> to pci_enable_msi - after that it Just Works(tm).
>>
>> Are there any gotchas that I'm missing? Would a patch to do this
>> be accepted?
> ..
> 
> Don't even dream about it for now.  The driver is unstable enough
> without throwing MSI into the works.
..

Oh, wait a minute.. I misread "sata_nv" as "sata_mv" there.

No comment on "sata_nv".

(we really oughta rename one of those two..)

Re: Enabling MSI in sata_nv

[Greg Freemyer]

On Dec 2, 2007 10:07 PM, Philip Langdale <philipl@overt.org> wrote:
> Hi all,
>
> At least for my hardware (MCP55), the sata controller supports MSI
> and it seems that turning it on is as simple as inserting the call
> to pci_enable_msi - after that it Just Works(tm).
>
> Are there any gotchas that I'm missing? Would a patch to do this
> be accepted?
>
> --phil

I don't know if it is relevant, but I had to disable MSI to get a
MCP55 NIC to work under 2.6.22.

See https://bugzilla.novell.com/show_bug.cgi?id=287017#c1 for details
if your curious.

Greg
-- 
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Litigation Triage Solutions Specialist
http://www.linkedin.com/in/gregfreemyer
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Re: Enabling MSI in sata_nv

[Jeff Garzik]

Greg Freemyer wrote:
> On Dec 2, 2007 10:07 PM, Philip Langdale <philipl@overt.org> wrote:
>> Hi all,
>>
>> At least for my hardware (MCP55), the sata controller supports MSI
>> and it seems that turning it on is as simple as inserting the call
>> to pci_enable_msi - after that it Just Works(tm).
>>
>> Are there any gotchas that I'm missing? Would a patch to do this
>> be accepted?
>>
>> --phil
> 
> I don't know if it is relevant, but I had to disable MSI to get a
> MCP55 NIC to work under 2.6.22.

MSI is pretty flaky, but we default it to 'on' for AHCI, which is the 
"enhanced mode" side of the sata_nv chip.

So it is likely that it works on newer boards -- but even though Mark 
Lord's response was mistaken (he thought sata_mv was being discussed), 
he was right too...  sata_nv has stability problems and I would prefer 
not to enable MSI just yet, until we cure the other problems.

	Jeff

Re: Enabling MSI in sata_nv

[Jeff Garzik]

Mark Lord wrote:
> Mark Lord wrote:
>> Philip Langdale wrote:
>>> Hi all,
>>>
>>> At least for my hardware (MCP55), the sata controller supports MSI
>>> and it seems that turning it on is as simple as inserting the call
>>> to pci_enable_msi - after that it Just Works(tm).
>>>
>>> Are there any gotchas that I'm missing? Would a patch to do this
>>> be accepted?
>> ..
>>
>> Don't even dream about it for now.  The driver is unstable enough
>> without throwing MSI into the works.
> ..
> 
> Oh, wait a minute.. I misread "sata_nv" as "sata_mv" there.

FWIW:  Marvell says they run with MSI enabled on 6440 (mvsas) in their 
vendor driver, but not on any of the 50xx and 60xx variants supported by 
sata_mv.

Maybe that's changed in the past year with 7042, I dunno.  But that's 
the latest info I have.

	Jeff

Re: Enabling MSI in sata_nv

[Philip Langdale]

Jeff Garzik wrote:
> 
> MSI is pretty flaky, but we default it to 'on' for AHCI, which is the
> "enhanced mode" side of the sata_nv chip.

If it's new enough. MCP55 has no ahci mode.

> So it is likely that it works on newer boards -- but even though Mark
> Lord's response was mistaken (he thought sata_mv was being discussed),
> he was right too...  sata_nv has stability problems and I would prefer
> not to enable MSI just yet, until we cure the other problems.

Fair enough. Well, just chalk me down as a data point where it seems
to be working.

--phil