ISDN cards and SMP

ISDN cards and SMP

[John Beardmore]

I've tried using a Sedlbauer speedcard ISDN controller under Alpha
RH6.2.

This works fine with a single processor kernel, but the module fails to
load with a kernel compiled for SMP.

I gather this is true for all the Isdn4Linux drivers, though as I have a
three processor machine, this is a real pain !

Advice seems to be to get an external TA of some kind, but that would
seem likely to add to ping times, and maybe to create a bottleneck if I
ever get 128k or compression to my ISP !

So, two questions:

  1) are there any fixes for this problem in the pipeline

and if not,

  2) how easy would it be for the kernel novice to adapt a uniprocessor
     driver to survive in the SMP environment ?


Cheers, J/.
-- 
John Beardmore

Re: ISDN cards and SMP

[David Woodhouse]

wookie@wookie.demon.co.uk said:
>  This works fine with a single processor kernel, but the module fails
> to load with a kernel compiled for SMP.

> I gather this is true for all the Isdn4Linux drivers, though as I have
> a three processor machine, this is a real pain !

The HiSax driver should be fine - I use it 100% of the time (or at least
100% of the time we have power to the house) on my SMP box at home, without 
trouble. I see no reason why the other drivers would have problems.

If you're having problem with modules loading, there's probably a
compilation problem. If you're using a distro kernel, check it's installed
properly. If you're building your own, rebuild it and the modules.

--
dwmw2

Re: ISDN cards and SMP

[John Beardmore]

In message <4947.1003748210@redhat.com>, David Woodhouse 
<dwmw2@infradead.org> writes
>wookie@wookie.demon.co.uk said:

>>  This works fine with a single processor kernel, but the module fails
>> to load with a kernel compiled for SMP.
>
>> I gather this is true for all the Isdn4Linux drivers, though as I have
>> a three processor machine, this is a real pain !
>
>The HiSax driver should be fine -

This is hisax.  What version are you using ?  Maybe it's been sorted in 
the last year or so ?


> I use it 100% of the time (or at least
>100% of the time we have power to the house) on my SMP box at home,

:)   !


> without
>trouble. I see no reason why the other drivers would have problems.

OK, but I've been told by other people that there are problems and this 
is consistent with my experience of this release.


>If you're having problem with modules loading, there's probably a
>compilation problem.

It seems odd that that the module compiles and links OK, and loads into 
a uniprocessor kernel if it's broken in any way.  Or can it be broken in 
some subtle SMP specific way ?


> If you're using a distro kernel, check it's installed
>properly.

I've built it from the sources that shipped with RH 6.2 using the GUI 
tool to specify SMP support.  I think it's installed properly in as far 
as all three CPUs get used once its installed.  Very cute !  Roll over 
NT etc !


> If you're building your own, rebuild it and the modules.

I can do, but I'd like to know what to do differently first.


Cheers, J/.
-- 
John Beardmore

Re: ISDN cards and SMP

[David Woodhouse]

wookie@wookie.demon.co.uk said:
>  This is hisax.  What version are you using ?  Maybe it's been sorted
> in  the last year or so ? 

I've used the 2.2 kernels shipped with Red Hat 7.0 and 7.1, briefly. This 
box has been running various 2.4 kernels since 2.4.0-test10, and is now 
running the Red Hat 7.2 release kernel. None of them have had any ISDN 
problems.

>  I've built it from the sources that shipped with RH 6.2 using the GUI
>  tool to specify SMP support.  I think it's installed properly in as
> far  as all three CPUs get used once its installed.  Very cute !  Roll
> over  NT etc !

Why rebuild? An SMP kernel is shipped, with matching modules etc.

> > If you're building your own, rebuild it and the modules.
> I can do, but I'd like to know what to do differently first. 

Difficult to say, without actually having seen the error you're getting. 
Try turning CONFIG_MODVERSIONS off and rebuilding both kernel and modules, 
for a start.

--
dwmw2