mpslsi0 : Trying sleep, but thread marked as sleeping prohibited

Desai, Kashyap Kashyap.Desai at
Wed Feb 22 14:06:50 UTC 2012


I am doing some code changes in mps dirver. While working on those changes, I come to know about something which is new to me.
Some expert help is required to clarify my doubt.

1. When any irq is register with FreeBSD OS, it sets " TDP_NOSLEEPING" pflag. It means though irq in freebsd is treated as thread,
We cannot sleep in IRQ because of " "TDP_NOSLEEPING " set.
2. In mps driver we have below code snippet in ISR routine.

    mps_dprint(sc, MPS_TRACE, "%s\n", __func__);

I wonder why there is no issue with above code ? Theoretical we cannot sleep in ISR. (as explained in #1)
Any thoughts ?

3. I recently added few place msleep() instead of DELAY in ISR context and I see 
" Trying sleep, but thread marked as sleeping prohibited".

` Kashyap

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