Messages in this thread Patch in this message | | | Date | Thu, 22 Apr 2010 12:09:38 -0700 | From | Greg KH <> | Subject | [127/197] Staging: comedi: usbdux.c: fix locking up of the driver when the comedi ringbuffer runs empty |
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2.6.32-stable review patch. If anyone has any objections, please let us know.
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From: Bernd Porr <berndporr@f2s.com>
commit d4c3a56587af3edbe5f618b20e800e9f9fde13cb upstream.
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 <berndporr@f2s.com> Signed-off-by: Leann Ogasawara <leann.ogasawara@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- 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); }
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