Hi again,

I also work with devices on the VME bus. The approach we took is to map
all the devices into userspace, and use Xenomai for RT performance. This
avoids the need to write drivers for all the devices. The RT-performance
of Xenomai is quite good: the jitter on a timer-interrupt is always less
than 20usec, even under high load, where standard Linux only achieves
this in a no load situatieo, under high load standard Linux has a jitter
of over 10 msec.

Good advice, I will investigate in this direction.

The setup we choose was to have a RT-interrupt handler and a RT IOCTL
call "WAIT_FOR_INTERRUPT". This is a slightly modified version from the
Motorola driver (I guess that you also use the Tundra chipset to access
the VME-bus).

Yes, I do. It is the Tsi148 in fact. I'll be interested to see some sample code of yours, if it doesn't violate some restrictions ofcourse.

Here you can wait for a specific VME interrupt-level, and
it returns the vector number. So you can have several applications
connect to the same VME driver, but all on different levels.

So, if I understand you correctly, you altered the Motorola driver in order for it to be able to communicate with user spae programms through Xenomai. Which version of Xenomai ws that? I tried to test Xemonai 2.0 on my setup but it iterfred somehow with SSH configuration and thats why i dropped it.

Many thanks,

Konstantin