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authorIan Abbott <abbotti@mev.co.uk>2010-06-18 12:11:28 +0100
committerGreg Kroah-Hartman <gregkh@suse.de>2010-06-30 08:18:14 -0700
commit6c2fd308045ba902fbe9f4408daa7b949fa8f5a1 (patch)
treef09e672e7f07666e217ae067c5ba043fbfdbe66e /drivers/staging
parent44176d9f8265de799512f833ca4d9785aa016b3a (diff)
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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.c9
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;