Problem access ioport .....

webquinty · 12-04-2008, 09:02 AM

Hello,

I have tried to access ioport to read some information from pc/104 board, but I have a small problem.

After request_region, in my case, request_region(ox150 ,8,"MyBoard")
I have tried to read a byte with inb an always return me the same value 0xFF, but If I try to write a byte (bit 0 is a led) ,I can turn off and turn on the led.

So, Could somebody tell me why can write a register without problems and can not read a byte???

Best regards.

jlinkels · 12-06-2008, 04:55 PM

It might be a write-only register. Some registers behave like that.

jlinkels

webquinty · 12-08-2008, 09:54 AM

Quote:

Originally Posted by jlinkels

It might be a write-only register. Some registers behave like that.

jlinkels

Hello,

Registers that I have tried to read are R/W.
But I read some infromation that it is necessary to compile driver at least with this option -O2.
I will try to do it, perhaps this is my problem.

Thanks a lot ans best regards