[Xenomai-help] RTDM and user space hardware drivers

["M. Koehrer" <mathias_koehrer@domain.hid>]

Hi everybody,

the RTDM API is really very good as API for drivers. 
I have a real time (Xenomai) application in user space that has to access PCI boards.
The "classical" approach is now to use a kernel driver and to use RTDM as interface
between the user space application an the kernel space driver.
However, for performance issues, I prefer to write a pure user mode driver.
As the memory of the PCI board can be accesses from user space (using /dev/mem) 
I want to write a pure user space driver  as this seems to me more efficient (and easier to debug) than
a kernel driver.
Also, only one application is accessing the driver at a time, I can link the driver directly to my application.

My questions are now:
1. Is it possible to use the RTDM API also for pure user space drivers?

2. Is there any experience concerning the performance of a user space driver versus a kernel space
driver?
In my use case, I have to write and read about 60 byte (each direction) of (block) data to/from the PCI I/O system.

Thanks for any ideas or hints on that!

Regards

Mathias


-- 
Mathias Koehrer
mathias_koehrer@domain.hid


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