The patch below does not apply to the 3.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From abe46b8932dd9a6dfc3698e3eb121809b7b9ed28 Mon Sep 17 00:00:00 2001
From: Ian Abbott <abbotti@xxxxxxxxx>
Date: Fri, 27 Feb 2015 16:04:42 +0000
Subject: [PATCH] staging: comedi: adv_pci1710: fix AI INSN_READ for non-zero
channel
Reading of analog input channels by the `INSN_READ` comedi instruction
is broken for all except channel 0. `pci171x_ai_insn_read()` calls
`pci171x_ai_read_sample()` 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_read_sample()`
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.
Note that when the bug first appeared, it was `pci171x_ai_dropout()`
that was called with the wrong parameter value. `pci171x_ai_dropout()`
got replaced with `pci171x_ai_read_sample()` in commit 7fd2dae2500d
("staging: comedi: adv_pci1710: introduce pci171x_ai_read_sample()").
Fixes: 16c7eb6047bb ("staging: comedi: adv_pci1710: always enable PCI171x_PARANOIDCHECK code")
Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx> # 3.16+
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
diff --git a/drivers/staging/comedi/drivers/adv_pci1710.c b/drivers/staging/comedi/drivers/adv_pci1710.c
index 9800c01e6fb9..3f72451d2de0 100644
--- a/drivers/staging/comedi/drivers/adv_pci1710.c
+++ b/drivers/staging/comedi/drivers/adv_pci1710.c
@@ -426,7 +426,6 @@ static int pci171x_ai_insn_read(struct comedi_device *dev,
unsigned int *data)
{
struct pci1710_private *devpriv = dev->private;
- unsigned int chan = CR_CHAN(insn->chanspec);
int ret = 0;
int i;
@@ -447,7 +446,7 @@ static int pci171x_ai_insn_read(struct comedi_device *dev,
if (ret)
break;
- ret = pci171x_ai_read_sample(dev, s, chan, &val);
+ ret = pci171x_ai_read_sample(dev, s, 0, &val);
if (ret)
break;
--
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