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Subject: Re: svn commit: r287892 - head/sys/dev/usb/wlan
To: Adrian Chadd <adrian@FreeBSD.org>, src-committers@freebsd.org,
 svn-src-all@freebsd.org, svn-src-head@freebsd.org
References: <201509170301.t8H31KdP042687@repo.freebsd.org>
From: Hans Petter Selasky <hps@selasky.org>
Message-ID: <55FA6C62.6010705@selasky.org>
Date: Thu, 17 Sep 2015 09:31:46 +0200
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On 09/17/15 05:01, Adrian Chadd wrote:
> Author: adrian
> Date: Thu Sep 17 03:01:19 2015
> New Revision: 287892
> URL: https://svnweb.freebsd.org/changeset/base/287892
>
> Log:
>    Use DELAY() rather than usb_pause_mtx() - the latter releases the lock
>    before waiting, which prevents the lock from really acting like
>    a hardware serialiser.  Sigh.
>
> Modified:
>    head/sys/dev/usb/wlan/if_rsu.c
>

This cause a lot more CPU to be burnt. Is there no other way to fix 
this? Using an SX lock?

--HPS