From: H Hartley Sweeten <hsweeten@visionengravers.com>
Date: Tue, 9 Sep 2014 23:16:06 +0000 (-0700)
Subject: staging: comedi: usbduxsigma: prevent "empty acquisition" async commands
X-Git-Tag: fixes-for-v3.18-merge-window~15^2~483
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=aaa0c2f77bee1f0834d549e9ca937fb2ecb6cda1;p=pandora-kernel.git

staging: comedi: usbduxsigma: prevent "empty acquisition" async commands

This driver currently allows a cmd->stop_src == TRIG_COUNT with a cmd->stop_arg
of 0 for both the analog input and output async commands. The (*do_cmd) for
both subdevices sets up and starts the command without handling the "empty
acquisition". This results in the interrupt functions trying to transfer 0 data
samples.

Validate that the cmd->stop_arg is >= 1 in the (*do_cmdtest) to prevent the
"empty acquisition".

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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