Messages in this thread | | | Date | Sat, 21 Jul 2007 01:59:01 +0400 | From | "Manu Abraham" <> | Subject | Re: [PATCH 5/7] I/OAT: Add support for MSI and MSI-X |
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On 7/21/07, Nelson, Shannon <shannon.nelson@intel.com> wrote: > Manu Abraham [mailto:abraham.manu@gmail.com] > >Sorry for being not clear. What i was asking is thus: > > > >A device that has legacy interrupts and MSI-X. I was thinking that if > >MSI-X failed one should fall back to MSI mode (single message), that's > >what i was assuming. > > > >In such a case, i do enable MSI-X mode on the device, when the request > >for 2 ^ n number of messages (where messages can be a max of 32), If > >the request fails one falls into a single message mode, ie MSI ? > > > > > >> What device do you have in mind? > > > > > >The device that i have in mind is a SAA7160. > > Notice our code looks at the return from pci_enable_msix() - it will > give you a hint whether MSI-X is not supported (returns < 0) or you > simply asked for too many (returns > 0). If the former, then fallback > to legacy; if the latter, try MSI-X with only one interrupt, which > essentially emulates MSI mode.
Ok. Thanks for clearing it up. So the idea would be that if pci_enable_msix() for "n" number of messages failed, then settle down for 1 message, which is equivalent to MSI mode - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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