On 2016-10-15 06:30, Bharat Kumar Gogada wrote:
On Sat, 15 Oct 2016 12:37:55 +0000
Bharat Kumar Gogada <bharat.kumar.gog...@xilinx.com> wrote:
> 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
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
advertises MSI-X support and that your devices do support it as well,
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 ?
Data field is used to indicate which interrupt number is used. It does
not need to start at 0.
You have 32 consecutive interrupts starting from some arbitrary base.
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