Polling for Linux kernel device drivers

[Saul Thurrowgood]

Using udelay usually sleeps for at least 35 usecs because the linux
scheduler takes time to swap processes. You need to use rtlinux for any
actual hard real-time processing - www.rtlinux.org.

Saul.

On Tue, 2 Oct 2001, James Macnicol wrote:

> Hello,
> 
> 	We are trying to write a device driver for a data aquisition card
> (ISA bus) that is only capable of doing polled I/O (no interrupts).  We need
> to poll every 10 microseconds or so.  Since this is shorter than a jiffy we
> can't use kernel timers.  It is possible to make it work using udelay() calls
> but this ties up the kernel rather badly and causes the disk to make funny
> noises....  Does anyone know of any drivers out there that already do this
> sort of thing (that we can crib code from) or just know what the best way
> to approach this problem is ?
> 
> 
> 
> Thanks.
> 
> 
> 
> --
> James Macnicol
> j-macnicol at adfa.edu.au
>