On 05/09/2011 03:55 PM, Greg KH wrote:
On Mon, May 09, 2011 at 10:35:42AM +0200, ÐÐÐÐÐÐ ÐÐÐÐÑ wrote:
Hello,
I have been using Prolific USB to Serial driver (pl2303) for over a year. When
I upgraded from 2.6.26 to 2.6.33, the driver lost the ability to send data.
When I checked the source code, it seemed that there were some changes in usb-
serial interface, pl2303 lost write method, and several calls changed in name
and code.
Who can I contact in order to work on a patch? I am willing to contribute, but
I believe I would require guidance.
What specifically stopped working?
Have you checked your line settings to verify that they are now correct?
How are you writing to the device from userspace?
The driver changed, yes, but it should still be working.
Could this have something to do with the issue discussed at
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/661321
("Opening /dev/ttyUSB0 hangs, pl2303.ko module")?
See in particular Comment 12:
".. After much researching it seems this is NOT a driver bug but a
CHANGE in the kernel Serial API semantics.
What has happened is that the API now blocks when a Serial device is not
indicating it is ready. This included 'open' on a serial device which
now can block.
Since lots of RS232 serial devices do not bother with any control
signals such as DCD (data carrier detect) they never indicate they are
ready and open blocks. This is the 'HANG' we are seeing. .."
Regards
Jon KÃre Hellan, Trondheim, Norway
thanks,
greg k-h
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