Messages in this thread | | | Date | Tue, 19 Mar 2013 14:18:59 -0400 (EDT) | From | Alan Stern <> | Subject | Re: gm45 intel gfx can generate non-MSI irq# in MSI mode (was Re: [PATCH] drm/i915: stop using GMBUS IRQs on Gen4 chips (was Re: [3.9-rc1] irq 16: nobody cared (was [3.9-rc1] very poor interrupt respo |
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On Tue, 19 Mar 2013, Daniel Vetter wrote:
> > That might be misleading. It's possible that the erroneous IRQs _are_ > > being issued but you're simply not aware of them. If the kernel thinks > > that no device is using IRQ 16 then it will leave that IRQ disabled. > > I guess I should have phrased it more precisely, but that's exactly > what I expect is happening on my machine: I don't have anything on > irq16 (i.e. in non-msi mode the gfx interrupt isn't shared) and hence > the irq is completely disabled. Which obviously makes it impossible > for me to reproduce the issue. To test that theory, is there a quick > way to force-enable a given interrupt, short of just hacking up a 2nd > dummy irq handler in my driver?
I don't know of any way. In fact, I have been thinking of writing a test driver module, with a module parameter telling it which IRQ number to register for. It seems like the sort of thing that would be useful to have, from time to time.
Alan Stern
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