staging: comedi: addi_apci_2032: only disable triggered interrupts

The interrupt handler disables all interrupt sources when a valid
interrupt occurs.  Just disable the triggered interrupt source so we can
still get interrupts for the other interrupt source.

Also add a comment indicating why the triggered interrupt source is
disabled.  The interrupt sources are level-sensitive and indicate
hardware errors that are likely to be persistent, so if we reenabled
them they would just keep triggering repeatedly.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/addi_apci_2032.c b/drivers/staging/comedi/drivers/addi_apci_2032.c
index 4c348dd2a5d5143b75ddd2525cbe26e199954d6a..98691fdfbd48ce6cc4466bafe7109325ab8bf790 100644 (file)
--- a/drivers/staging/comedi/drivers/addi_apci_2032.c
+++ b/drivers/staging/comedi/drivers/addi_apci_2032.c
@@ -246,7 +246,13 @@ static irqreturn_t apci2032_interrupt(int irq, void *d)
                return IRQ_NONE;
 
        val = inl(dev->iobase + APCI2032_INT_STATUS_REG) & 3;
-       outl(0x00, dev->iobase + APCI2032_INT_CTRL_REG);
+       /* Disable triggered interrupt sources. */
+       outl(~val & 3, dev->iobase + APCI2032_INT_CTRL_REG);
+       /*
+        * Note: We don't reenable the triggered interrupt sources because they
+        * are level-sensitive, hardware error status interrupt sources and
+        * they'd keep triggering interrupts repeatedly.
+        */
 
        if (comedi_buf_put(s->async, val))
                s->async->events |= COMEDI_CB_BLOCK | COMEDI_CB_EOS;