staging: comedi: amplc_pci224: remove "empty acquisition" async command

This driver currently allows a cmd->stop_src == TRIG_COUNT with a cmd->stop_arg
of 0. This causes the (*do_cmd) to immediately generate a COMEDI_CB_EOA event
without acquiring any data.

This "empty acquisition" async command is not really useful. Validate that the
cmd->stop_arg is >= 1 in the (*do_cmdtest) and remove the "empty acquisition"
code.

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>

diff --git a/drivers/staging/comedi/drivers/amplc_pci224.c b/drivers/staging/comedi/drivers/amplc_pci224.c
index fa179d9..3bbbb57 100644 (file)
--- a/drivers/staging/comedi/drivers/amplc_pci224.c
+++ b/drivers/staging/comedi/drivers/amplc_pci224.c
@@ -494,21 +494,16 @@ static void pci224_ao_start(struct comedi_device *dev,
        unsigned long flags;
 
        set_bit(AO_CMD_STARTED, &devpriv->state);
-       if (cmd->stop_src == TRIG_COUNT && devpriv->ao_stop_count == 0) {
-               /* An empty acquisition! */
-               s->async->events |= COMEDI_CB_EOA;
-               cfc_handle_events(dev, s);
-       } else {
-               /* Enable interrupts. */
-               spin_lock_irqsave(&devpriv->ao_spinlock, flags);
-               if (cmd->stop_src == TRIG_EXT)
-                       devpriv->intsce = PCI224_INTR_EXT | PCI224_INTR_DAC;
-               else
-                       devpriv->intsce = PCI224_INTR_DAC;
 
-               outb(devpriv->intsce, devpriv->iobase1 + PCI224_INT_SCE);
-               spin_unlock_irqrestore(&devpriv->ao_spinlock, flags);
-       }
+       /* Enable interrupts. */
+       spin_lock_irqsave(&devpriv->ao_spinlock, flags);
+       if (cmd->stop_src == TRIG_EXT)
+               devpriv->intsce = PCI224_INTR_EXT | PCI224_INTR_DAC;
+       else
+               devpriv->intsce = PCI224_INTR_DAC;
+
+       outb(devpriv->intsce, devpriv->iobase1 + PCI224_INT_SCE);
+       spin_unlock_irqrestore(&devpriv->ao_spinlock, flags);
 }
 
 /*
@@ -782,7 +777,7 @@ pci224_ao_cmdtest(struct comedi_device *dev, struct comedi_subdevice *s,
 
        switch (cmd->stop_src) {
        case TRIG_COUNT:
-               /* Any count allowed. */
+               err |= cfc_check_trigger_arg_min(&cmd->stop_arg, 1);
                break;
        case TRIG_EXT:
                /* Force to external trigger 0. */