Wayne Cuddy wrote:
>If I understand wait_queues correctly the process has to be sleeping before a
>wake_up call will have any effect (I.E. they are not queued). Can this be
>worked around with semaphores or some other method? I am open to ideas here.
>Any and all help is appreciated.
I apologize in advance if this is not quite right, having only done
"hello world" kernel modules thus far (plus a good deal of kernel source
browsing). I think you need to "unfold" the interruptible_sleep_on call
and do it yourself by adding current to the wait queue before checking
any cards, setting current->state = TASK_INTERRUPTIBLE, then checking
all cards and if none has data, calling schedule. When you get back
from schedule (i.e. your ISR has received data and done a wake_up) or
any card has data, remove yourself from the wait queue and set your
state to runnable. This hopefully gives you the "atomic check condition
and sleep if not satisfied" behavior.
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This archive was generated by hypermail 2b29 : Sun Sep 30 2001 - 21:00:58 EST