Re: How to simulate a device which generates an interrupt every 8.3 ms

[Jakob Bohm]

On 2020-12-10 12:07, Peter Maydell wrote:
> On Thu, 10 Dec 2020 at 05:28, Weiss, Howard <Howard.Weiss2@hologic.com> wrote:
> > Hi –
> >
> >
> >
> > I am writing a Windows 10 device driver which receives an interrupt from 
> > hardware every 8.3 ms.  I am simulating the hardware device in a linux QEMU/KVM 
> > VM with Windows 10 installed.  How do I program my simulated device to generate 
> > an interrupt every 8.3 ms? Under windows, I would generate a high resolution 
> > timer interrupt using the windows multi-media API.  What is the QEMU/KVM 
> > equivalent?
> Use a QEMUTimer. You can set the expiry period in nanoseconds.
> Note that you should probably not expect QEMU's timing to be
> accurate to exactly 8.3ms.
I'm guessing any mostly smooth 120Hz interrupt rate would be
fine.  Similar to the 55ms/18.2Hz PC Int08 signal that was
historically 0x10000 ticks per hour, 0x180000 + epsilon ticks/day.

Enjoy

Jakob
--
Jakob Bohm, CIO, Partner, WiseMo A/S.  https://www.wisemo.com
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