Hi!
I want to use poll() functionality (to properly handle select() and
poll() syscalls) in my char-device driver. The code for my kernel-side
poll() function is (a little bit simplified):
unsigned int my_poll(struct file *filp, struct poll_table_struct *wait)
{
unsigned int mask=0;
unsigned long flags;
poll_wait(filp, my_wait_queue, wait);
if ( any_data_available > 0)
mask |= POLLIN | POLLRDNORM;
return mask;
}
Where "my_wait_queue" is of "wait_queue_head_t" type,
"any_data_available" if the flag which tells if any data is available
within internal buffer.
When I load this driver and start user-space application wich calls
select() with 5 seconds timeout the select() returns after waiting
this timeout no matter when the data comes into the port (1,2,3
seconds). The return value is positive when the data available and 0
when no data comes, as it should be. The question is why select()
waits for the timeout even when data is available?
--
Denis
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