Re: [PATCH 2/2] Initial generic hypertransport interrupt support.

Eric W. Biederman
2006-07-12T03:06:51Z

Andi Kleen <ak@suse.de> writes:

> ebiederm@xmission.com (Eric W. Biederman) writes:
>
>> This patch implements two functions ht_create_irq and ht_destroy_irq
>> for use by drivers. Several other functions are implemented as helpers
>> for arch specific irq_chip handlers.
>
> What do you want to use it for? Normally all HT configuration should be handled
> by the BIOS and not messed with by the kernel.

I don't believe this is a typical HT configuration as you are thinking of it.

There is a hypertransport capability that implements a rough equivalent
of a per device ioapic. It is quite similar to MSI but with a different
register level interface.

Since native hypertransport devices do not implement a pin emulation mode
as native pci express devices do so if you want an interrupt you must support
the native hypertransport method.

The pathscale ipath-ht400 driver already in the kernel tree uses these
and uses so an ugly hack to make work that broke in the last round of
the msi cleanups. I also know of a driver under development for a
device that uses these as well.

So I want to use this so I can get irqs from native hypertransport
devices.

Eric