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| author |   Ian Abbott <abbotti@mev.co.uk> | 2010-06-18 12:11:28 +0100 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@suse.de> | 2010-06-30 08:18:14 -0700 |
| commit | 6c2fd308045ba902fbe9f4408daa7b949fa8f5a1 (patch) | |
| tree | f09e672e7f07666e217ae067c5ba043fbfdbe66e /drivers/staging | |
| parent | Staging: mrst-touchscreen: fix dereferencing free memory (diff) | |
| download | linux-dev-6c2fd308045ba902fbe9f4408daa7b949fa8f5a1.tar.xz linux-dev-6c2fd308045ba902fbe9f4408daa7b949fa8f5a1.zip | |
Staging: comedi: drivers: adl_pci9111: Fix AI commands in TRIG_FOLLOW case
I received a report that AI streaming acquisitions do not work properly
for the adl_pci9111 driver when convert_src is TRIG_TIMER and
scan_begin_src is TRIG_FOLLOW (and scan_begin_arg is therefore 0). This
seems to be down to the incorrect setting of dev_private->scan_delay in
pci9111_ai_do_cmd(). Under the previously stated conditions,
dev_private->scan_delay ends up set to (unsigned int)-1, but it ought to
be set to 0. The function sets it to 0 initially, and it only makes
sense to change it if both convert_src and scan_begin_src are set to
TRIG_TIMER.
Note: 'scan_delay' is the number of unwanted scans to discard after each
valid scan. The hardware does not support 'scan' timing as such, just a
regularly paced conversion timer (with automatic channel switching
between conversions). The driver simulates a scan period that is some
(>1) multiple of the conversion period times the scan length
(chanlist_len samples) by reading chanlist_len samples and discarding
the next scan_delay times chanlist_len samples.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/staging')
| -rw-r--r-- | drivers/staging/comedi/drivers/adl_pci9111.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/staging/comedi/drivers/adl_pci9111.c b/drivers/staging/comedi/drivers/adl_pci9111.c index 36a254cd4413..39d112b708e3 100644 --- a/drivers/staging/comedi/drivers/adl_pci9111.c +++ b/drivers/staging/comedi/drivers/adl_pci9111.c @@ -824,9 +824,12 @@ static int pci9111_ai_do_cmd(struct comedi_device *dev, plx9050_interrupt_control(dev_private->lcr_io_base, true, true, false, true, true); - dev_private->scan_delay = - (async_cmd->scan_begin_arg / (async_cmd->convert_arg * - async_cmd->chanlist_len)) - 1; + if (async_cmd->scan_begin_src == TRIG_TIMER) { + dev_private->scan_delay = + (async_cmd->scan_begin_arg / + (async_cmd->convert_arg * + async_cmd->chanlist_len)) - 1; + } break; |