Re: Determining if ISA card exists using user space driver.

[alfonso_acosta_mail@yahoo.es]

Hugh de Burgh wrote:
> I've been writing a user space driver for a proprietary ISA card for 
> linux.I've used ioperm to give me access to the ports (using inw, outw) 
> and mmap of /dev/mem to give me access to the memory.
> 
> This all works great if my ISA card is present.
> But if it doesn't exist my code seg faults when I try to access the 
> memory or ports which aren't there.
> 
> So my question is... how can I determine if the card exists or not 
> without my code seg faulting?
> 

Just use /dev/port for accesing the ports.

You can see port_fops in drivers/char/mem.c for details. The driver 
first checks if the port is accesible, and that is what you need ;)

A more friendly way to learn how /dev/port works should be reading 
section 2.2 of:

http://www.tldp.org/HOWTO/IO-Port-Programming.html

Cheers

Alfonso Acosta




--
Kernelnewbies: Help each other learn about the Linux kernel.
Archive:       http://mail.nl.linux.org/kernelnewbies/
FAQ:           http://kernelnewbies.org/faq/