From: Ian Abbott <[email protected]> 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 <[email protected]> --- 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 36a254c..39d112b 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; -- 1.7.1 _______________________________________________ devel mailing list [email protected] http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
