Messages in this thread | | | Subject | Discovering select(2) parameters from driver's poll method | From | Ozan Eren Bilgen <> | Date | Fri, 09 Jun 2006 14:50:51 +0300 |
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*** Please CC me your responses ***
Hi,
I am writing a device driver and I have problem with poll method. For some reason, I need learn the timeout and descriptor sets of select(2) call. Other words to say, if the user space process calls:
select(n, &readfds, NULL, &exceptionfds, &tv);
With the help of my poll implementation in device driver, I want to learn that only the write fds is empty. I am also interested in the value of timeout parameter. Please let me know if this is possible.
By the way, I checked out some Linux device drivers, which are implemented poll method, and related books like LDD. Everywhere, poll_wait is called for both read and write queues, without taking the select(2) call's parameters into account. For example it still waits for the read queue although the select call was looking only for write fds. My second question is, why a poll method queries all the queues, instead of querying only the necessary one?
Thank you in advance,
Ozan Eren Bilgen
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