Re: pci_enable_msi() for everyone?
From: Luben Tuikov
Date: Tue Jun 07 2005 - 12:46:23 EST
On 06/07/05 01:46, Adam Belay wrote:
> On Mon, Jun 06, 2005 at 10:22:03PM -0700, Greg KH wrote:
>
>>On Mon, Jun 06, 2005 at 05:26:32PM -0700, Roland Dreier wrote:
>>
>>> davej> What if MSI support has been disabled in the bridge due to
>>> davej> some quirk (like the recent AMD 8111 quirk) ? Maybe the
>>> davej> above function should check pci_msi_enable as well ?
>>>
>>> Greg> Yes, you are correct. I said it wasn't tested :)
>>>
>>>Huh? If a host bridge doesn't support MSI, and a device below it has
>>>its MSI capability enabled, we're in big trouble. Because that device
>>>is going to send interrupt messages whether the bridge likes it or
>>>not.
>>
>>No, that device would never get MSI enabled on it. See the patch I
>>posted to make sure I didn't get it wrong...
>>
>>thanks,
>>
>>greg k-h
>
>
> How are we handling the case where a device has multiple MSI messages.
> Is any driver interaction needed for that? Will this change affect it?
> I haven't had a chance to look through the MSI code yet.
>
> Thanks,
> Adam
Yes, this is a very good point (PCI MSI-X).
All in all, given all the hardware quirks of both
PCI bridges and PCI devices, I'd leave PCI MSI
control to the PCI LLDD.
Luben
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