commit abe46b8932dd upstream Reading of analog input channels by the `INSN_READ` comedi instruction is broken for all except channel 0. `pci171x_insn_read_ai()` calls `pci171x_ai_dropout()` with the wrong value for the third parameter. It is supposed to be the current index in a channel list (which is always of length 1 in this case, so the index should be 0), but instead it is passing the actual channel number. `pci171x_ai_dropout()` checks the channel number encoded in the raw sample value read from the hardware matches the channel number stored in the specified index of the previously set up channel list and returns `-ENODATA` if it doesn't match. Since the index should always be 0 in this case, the match will fail unless the channel number is also 0. Fix it by passing 0 as the channel index. Fixes: 16c7eb6047bb ("staging: comedi: adv_pci1710: always enable PCI171x_PARANOIDCHECK code") Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx> --- Sorry, the original upstream commit didn't apply! --- drivers/staging/comedi/drivers/adv_pci1710.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/staging/comedi/drivers/adv_pci1710.c b/drivers/staging/comedi/drivers/adv_pci1710.c index d02df7d..57b7bc2 100644 --- a/drivers/staging/comedi/drivers/adv_pci1710.c +++ b/drivers/staging/comedi/drivers/adv_pci1710.c @@ -455,7 +455,6 @@ static int pci171x_insn_read_ai(struct comedi_device *dev, struct comedi_insn *insn, unsigned int *data) { struct pci1710_private *devpriv = dev->private; - unsigned int chan = CR_CHAN(insn->chanspec); int ret = 0; int i; @@ -477,7 +476,7 @@ static int pci171x_insn_read_ai(struct comedi_device *dev, break; val = inw(dev->iobase + PCI171x_AD_DATA); - ret = pci171x_ai_dropout(dev, s, chan, val); + ret = pci171x_ai_dropout(dev, s, 0, val); if (ret) break; -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html