From 4a4c1b1d5a1d1f083ea9a9fe8b179bfa9e62e12a Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Tue, 30 Oct 2018 17:23:54 +0000 Subject: [PATCH] staging: comedi: ni_labpc_common: Use insn->n in AO insn_write handler The `insn_write` handler for the AO subdevice (`labpc_ao_insn_write()`) currently ignores `insn->n` (the number of samples to write) and assumes a single sample is to be written. But `insn->n` could be 0, meaning no samples should be written, in which case `data[0]` is invalid. Follow the usual Comedi guidelines and change `labpc_ao_insn_write()` to write the specified number of samples. This fixes the assumption that `data[0]` is valid. Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/ni_labpc_common.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/staging/comedi/drivers/ni_labpc_common.c b/drivers/staging/comedi/drivers/ni_labpc_common.c index 7fa2d39..406952f 100644 --- a/drivers/staging/comedi/drivers/ni_labpc_common.c +++ b/drivers/staging/comedi/drivers/ni_labpc_common.c @@ -906,7 +906,9 @@ static int labpc_ao_insn_write(struct comedi_device *dev, { const struct labpc_boardinfo *board = dev->board_ptr; struct labpc_private *devpriv = dev->private; - int channel, range; + unsigned int channel; + unsigned int range; + unsigned int i; unsigned long flags; channel = CR_CHAN(insn->chanspec); @@ -932,9 +934,10 @@ static int labpc_ao_insn_write(struct comedi_device *dev, devpriv->write_byte(dev, devpriv->cmd6, CMD6_REG); } /* send data */ - labpc_ao_write(dev, s, channel, data[0]); + for (i = 0; i < insn->n; i++) + labpc_ao_write(dev, s, channel, data[i]); - return 1; + return insn->n; } /* lowlevel write to eeprom/dac */ -- 2.7.4