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Commit ce987a8a authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
Browse files

staging: comedi: addi_apci_3120: prevent deadlock in apci3120_ao_insn_write() 



The DA_READY bit (0x0001) in the status register needs to be set before the
analog outputs can be updated.

Use comedi_timeout() to prevent a deadlock condition while waiting for the
DA_READY bit to get set.

Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 695f34ce

drivers/staging/comedi/drivers/addi-data/hwdrv_apci3120.c

+17 −4
Original line number Diff line number Diff line
@@ -1923,21 +1923,34 @@ static int apci3120_do_insn_bits(struct comedi_device *dev, 
	return insn->n;

}



static int apci3120_ao_ready(struct comedi_device *dev,

			     struct comedi_subdevice *s,

			     struct comedi_insn *insn,

			     unsigned long context)

{

	unsigned int status;



	status = inw(dev->iobase + APCI3120_RD_STATUS);

	if (status & 0x0001)	/* waiting for DA_READY */

		return 0;

	return -EBUSY;

}



static int apci3120_ao_insn_write(struct comedi_device *dev,

				  struct comedi_subdevice *s,

				  struct comedi_insn *insn,

				  unsigned int *data)

{

	unsigned int ui_Channel;

	unsigned short us_TmpValue;

	int ret;



	ui_Channel = CR_CHAN(insn->chanspec);



	data[0] = ((((ui_Channel & 0x03) << 14) & 0xC000) | data[0]);



	do {			/* Waiting of DA_READY BIT */

		us_TmpValue = inw(dev->iobase + APCI3120_RD_STATUS) & 0x0001;

	} while (us_TmpValue != 0x0001);

	ret = comedi_timeout(dev, s, insn, apci3120_ao_ready, 0);

	if (ret)

		return ret;



	if (ui_Channel <= 3)

		/*