Messages in this thread | | | From | Rusty Russell <> | Subject | Re: [Patch/RFC]: check CONFIG_GENERIC_HARDIRQS for request/free_irq in interrupt.h | Date | Fri, 30 May 2008 13:36:02 +1000 |
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On Friday 30 May 2008 04:32:58 Christian Borntraeger wrote: > Am Donnerstag, 29. Mai 2008 schrieb Martin Schwidefsky: > > On Thu, 2008-05-29 at 17:41 +0200, Christian Borntraeger wrote: > > > I currently try to evaluate virtio_console for kvm on s390 and got > > > the following problem: > > > > > > virtio_console uses hvc_alloc with irq=0. That means, register_irq > > > and free_irq are never called by hvc_console.c, but the linker will > > > still complain about unknown references to free_irq and request_irq. > > > > > > As the whole kernel/irq folder depends on CONFIG_GENERIC_HARDIRQS > > > it seems consistent to declare all functions from kernel/irq only if > > > CONFIG_GENERIC_HARDIRQS is set. Otherwise we can use empty functions. > > > > > > This patch does that for register_irq and free_irq. > > > > > > Comments? > > > > Please don't. So far whenever the linker complained about the missing > > register_irq/free_irq functions it has been a bug in a Kconfig file. > > We should not silently accept code that requires the concept of an > > irq-line when there is no such thing on a s390. > > Ok, convinced. > > I will look if I can modify virtio_console to get rid of hvc_console. > Reading all the comments, it appears that Rusty is not really happy with > all the dependencies/limitations that hvc_console brings to virtio_console. > > Rusty, be prepared.... ;-) > > Christian
OK, my plan was to at least allow the hook of notifiers in hvc_console, rather than relying on interrupts or nothing. Then expose "use interrupt to notify" and "use a backoff timer to notify" helpers and let the caller hook one up.
But it was a vague plan which may become unrecognisable when meeting reality...
Cheers, Rusty.
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