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Old 03-23-2005, 03:16 AM   #1
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Registered: Mar 2005
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Question poll_wait related


Please let me know the following things.

1. one of my application is doing a select() system
call and waiting for characters typed from
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

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

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 ?

Old 03-24-2005, 05:36 PM   #2
Senior Member
Registered: Jun 2004
Posts: 2,553

Rep: Reputation: 53
select registers a file descriptor
then select() indicates events on that file descriptor
Old 03-24-2005, 07:12 PM   #3
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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