Problem with wake_up using real-time scheduling

From: Zoltan Bus
Date: Tue Jun 30 2009 - 04:44:46 EST


Hello,

I have a problem on kernel 2.6.26.3. I have a real-time task which
uses the select system call to poll my audio driver. The sleeping task
is waken up by wake_up() from an interrupt handler.
The problem is, that the wake_up() function sometimes does not wake
up the task if real-time priority is used.

The try_to_wake_up() returns from the out_running section, because of the check

if (p->se.on_rq)
goto out_running;

There are no other tasks running when the poll function is called.

Is this a known problem? Is it fixed somehow in newer versions?
Unfortunately I do not have the possibility to change the newest kernel version.
I am a newbie at linux, thank you very much for your help.

Zoltan
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