Backchannel data missing

[keens312]

Hi Michael,

An issue was found in my driver, please have a look and give me advice.

On OSX 10.5 with USB connection, print with manual duplex. When first half is printed, the printer will send manual duplex code to host through backchannel. filter will receive it and display it.

The problem is that this manual duplex code will not be read by filter sometimes. This can be reproduced easily, just do the manual duplex printing twice, and one of it will not get the correct feedback.

I was wonder where the data was blocked. with USB analyser, it DID captured the data has been sent to Apple OSX. but filter just cannot read it from FD #3.

In my knowledge, the data from USB should go to Apple IOKit at first, then CUPS system, then my filter.

Could you give me some suggestion about how to debug this or get the log about bachchannel?

Thanks
Keene