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SubjectRe: Question about linux drivers

Hello.

> 1. Is there any centralized "organ" to coordinate and assign official
> major numbers?

Yes. Look at "Documentation/devices.txt".

However, I *strongly* suggest to use dinamic assignments of a major number.
There's plenty of documentation about this feature, but I can send you
the material if you need it.

If I and other hackers asked a major number for every thing we write
a driver for, Linux will already have a 64-bit kdev_t :)

> 2. Ditto, but applying to ioctl magic numbers?

You're on you own. Every device declares its headers. Once again, if
you want some advice, ask for it.

> 3. Since only one process runs while executing in the kernel, all
> other processes "hangs". How long is it reccomended/acceptable to
> "hold" the kernel before schedule() is/must be called? 1*HZ?

Definitely less. A few milliseconds at most. Use kernel timers for
anything longer than 10ms.

Best
/alessandro
--
__ o Tu vuo` fa` l'americano: sient'a me chi t'o fa fa`.
_`\<, (Renato Carosone)
__( )/( )__ alessandro.rubini@linux.it +39-0382-529554

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