Re: Converting a device driver for real time kernel

[Sven-Thorsten Dietrich <sdietrich@novell.com>]

On Tue, 2010-02-09 at 09:32 +0000, Leggo, Adam (UK) wrote:
> Hello,
>  
> What is the best way of converting an existing device driver to work
> under a real-time kernel?
>  
> A device driver provided for a special serial card (Curtiss Wright SL240
> sFDFP card http://www.cwcembedded.com/products/0/1/461.html) works under
> vanilla Linux (SLES SP10 SP2 kernel 2.6.16.60-0.21-smp), but compiling
> the driver under the real time kernel (2.6.22.19-0.14-rt) the system
> locks up and crashes. The rt kernel is being used to write large amounts
> of data from the serial card to disk and testing has found the rt kernel
> has the best consistent write performance.
>  
> I have gone back to the supplier and they are not interested in
> developing a real time version of the driver. So I am trying to modify
> the driver myself. The driver code can be provided if anyone wants a
> look (released under GPLv2).
>  

Hi Adam,

Generally this list is focused on the mainline RT patch set, and not so
much on distro Kernels. 

I might be wrong, but out-of-tree drivers probably won't get too much
TLC here either.

That being said, your version of the SLERT Kernel is quite old.

I would suggest the following:

1. first update your system and reproduce the issue
2. file a bug and attach the driver source here:
http://bugzilla.novell.com
3. Report any specific error you could capture on a serial / net
console, and provide additional details for "locks up and crashes".

Thanks,

Sven


> Any assistance would be useful.
> 
> Regards,
> Adam Leggo 
>  
> 
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