Re: [PATCH] sparse_irq aka dyn_irq v13

From: H. Peter Anvin
Date: Sun Nov 16 2008 - 19:52:45 EST


Yinghai Lu wrote:
> H. Peter Anvin wrote:
>> It would, however, be a good idea if IOAPICs had their numbers assigned
>> at detection time, as opposed to when the interrupt is registered, thus
>> making it a stable number for a single boot, at least. The same is
>> probably true for MSI(-X); we could assign it a range of numbers when
>> the device is enumerated (as opposed to when a driver is activated), but
>> I don't know to what extent that is likely to cause more troubles than
>> it solves.
>
> how to find the range for MSIX, one device/func may need a lot. for example, niu driver could use 20 MSI-X for one port. (one dev/func)
> some could use 256. we only know that when driver is loaded.
> So as Eric said, just try to use 12bits (4k range) for them.
>

You can know how many vectors are exported in generic code. However,
using 4k per should be fine.

-hpa
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