Re: Backport of a 2.6.x USB driver to 2.4.32 - help needed

[Heiko Gerstung <heiko.gerstung@meinberg.de>]

Jesper Juhl wrote:
> in_atomic() is used to test if the kernel is in a state where sleeping
> is allowed or not. The 2.4.x kernel is not preemptive and has quite
> coarse grained SMP support (the BKL "Big Kernel Lock"), it didin't
> need in_atomic() in the same way as 2.6.x does.
OK, so I guess I can safely ommit this.

> schedule_timeout_uninterruptible() is used to sleep on a wait-queue,
> which 2.4.x does not have.
Is there any similiar functionality in a 2.4 kernel environment? A
pointer to a 2.4 kernel driver using such a mechanism would be a good
starter...

> [snip]
> Wouldn't it make more sense to work on improving PPS (I assume you are
> refering to NTP "pulse per second" btw) support in 2.6.x rather than
> backporting an USB driver to 2.4.x ???
Yes, but unfortunately I have no chance to do this and therefore I rely
on others to do this. Well, the same applies to [me] and [kernel
drivers], but I hoped that it might be easier to try and backport one
driver instead of trying to improve other people's code (maybe that is
what OPC stands for :-)), especially when this code has a much larger
impact on several parts of the kernel.

> [snip]
> The book "Linux Device Drivers" third edition is available for free
> online and describes 2.6.x USB drivers in a fair bit of detail.
> Earlier editions of the book describe the 2.4.x kernel (don't know if
> those are available for free, but it should be possible to get them
> from a bookstore in any case).
> 
> Getting hold of the second & third editions of LDD and comparing the
> USB info from both should give you some idea of where to start...
OK, I will try to do so, but I am afraid that I will run out of time in
the meantime.

Thank you very much for your help and your fast response.

Kind regards,
Heiko




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