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Old 03-23-2005, 04:16 AM   #1
rupeshk73
LQ Newbie
 
Registered: Mar 2005
Posts: 1

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Question poll_wait related


Hi

Please let me know the following things.

1. one of my application is doing a select() system
call and waiting for characters typed from
keyboard.
2. In the kernel we use a wrapper function which
uses poll_wait() inside.
3. This wrapper is called when user calls select().

4. In kernel I am replicating duart_int() ISR by my
own routine where the input characters are taken
from my buffer instead of keyboard.
5. When I do this all my string is seen properly in
tty->read_buf.

6. now this characters from my buffer is not read
into the application where select is used.
(It works properly for normal situations.)

Please let me know what is the trigger I need to
provide from kernel after my string is put into
tty->read_buf

In other way...

What is the signal, select() or poll_wait() has to
receive from kernel so that application starts
reading my charaters from tty->read_buf ?

Thanks
Rupesh
 
Old 03-24-2005, 06:36 PM   #2
foo_bar_foo
Senior Member
 
Registered: Jun 2004
Posts: 2,553

Rep: Reputation: 52
select registers a file descriptor
then select() indicates events on that file descriptor
 
Old 03-24-2005, 08:12 PM   #3
visaris
Member
 
Registered: Dec 2004
Distribution: gentoo
Posts: 190

Rep: Reputation: 30
I think you would have better luck posting this in a more advanced programming/kernel dev forum. Unless you want to get more responses like the previous one that is. I think your question may be a little advanced for this "newbie" forum. I understand the problem you are having, but I don't know the internels of the kernel at all, so I have no idea how to cause select to return like you need.
 
  


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