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From: "Desai, Kashyap" <Kashyap.Desai@lsi.com>
To: "freebsd-scsi@freebsd.org" <freebsd-scsi@freebsd.org>, freebsd-stable
	<freebsd-stable@freebsd.org>
Date: Wed, 22 Feb 2012 19:36:42 +0530
Thread-Topic: mpslsi0 : Trying sleep, but thread marked as sleeping prohibited
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Cc: "Justin T. Gibbs" <gibbs@freebsd.org>, "Kenneth D. Merry" <ken@freebsd.org>,
	"McConnell, Stephen" <Stephen.McConnell@lsi.com>
Subject: mpslsi0 : Trying sleep, but thread marked as sleeping prohibited
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Hi,

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" pfla=
g. 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__);
    mps_lock(sc);
    mps_intr_locked(data);
    mps_unlock(sc);

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


3. I recently added few place msleep() instead of DELAY in ISR context and =
I see=20
" Trying sleep, but thread marked as sleeping prohibited".


` Kashyap