RE: Why MSI is limited to 32 interrupts maximum
From: Bharat Kumar Gogada
Date: Sat Oct 15 2016 - 09:46:51 EST
> On Sat, 15 Oct 2016 12:37:55 +0000
> Bharat Kumar Gogada <bharat.kumar.gogada@xxxxxxxxxx> wrote:
> Hi Bharat,
> > Can anyone tell why MSI interrupts are limited to maximum 32
> > interrupts, even though we have 16bit message data register ?
> That's the very definition of the original PCI MSI: Up to 32 consecutive interrupts
> per function, and a single doorbell address.
> MSI-X lifts that restriction and offers up to 2048 interrupts that do not have to
> be contiguous can target individual doorbells. Assuming your MSI controller
> advertises MSI-X support and that your devices do support it as well, you'll be
> able to enjoy those.
Thanks Marc, so then only 5 bits of message data register will be used, so what is the purpose rest of the bits ?
> > Regards,
> > Bharat
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