From berndporr@f2s.com Fri Dec 18 10:03:41 2009 From: Bernd Porr Date: Fri, 27 Nov 2009 12:00:53 +0000 Subject: Staging: comedi: usbdux.c: fix locking up of the driver when the comedi ringbuffer runs empty To: gregkh@suse.de Message-ID: <4B0FBF75.1010108@f2s.com> Jan-Matthias Braun spotted a bug which locks up the driver when the comedi ring buffer runs empty and provided a patch. The driver would still send the data to comedi but the reader won't wake up any more. What's required is setting the flag COMEDI_CB_BLOCK after new data has arrived which wakes up the reader and therefore the read() command. Signed-off-by: Bernd Porr Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/usbdux.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/drivers/staging/comedi/drivers/usbdux.c +++ b/drivers/staging/comedi/drivers/usbdux.c @@ -1,4 +1,4 @@ -#define DRIVER_VERSION "v2.3" +#define DRIVER_VERSION "v2.4" #define DRIVER_AUTHOR "Bernd Porr, BerndPorr@f2s.com" #define DRIVER_DESC "Stirling/ITL USB-DUX -- Bernd.Porr@f2s.com" /* @@ -81,6 +81,8 @@ sampling rate. If you sample two channel * 2.1: changed PWM API * 2.2: added firmware kernel request to fix an udev problem * 2.3: corrected a bug in bulk timeouts which were far too short + * 2.4: fixed a bug which causes the driver to hang when it ran out of data. + * Thanks to Jan-Matthias Braun and Ian to spot the bug and fix it. * */ @@ -532,6 +534,7 @@ static void usbduxsub_ai_IsocIrq(struct } } /* tell comedi that data is there */ + s->async->events |= COMEDI_CB_BLOCK | COMEDI_CB_EOS; comedi_event(this_usbduxsub->comedidev, s); }