Next testing round: cups 1.5.3-0ubuntu2~ppa7 is uploaded to my PPA now and this respects uni-directional devices and gives some more messages in error_log.
Please repeat the tests with it (with and without blacklisting usblp) and attach syslog and error_log of the failing tests.
In addition, you can try to force uni-directional mode by
lpadmin -p <queue> -o usb-unidir-default=true
and restore to normal mode via
lpadmin -p <queue> -o usb-unidir-default=false
For <queue> the name of your print queue has to be inserted.
Please repeat your tests with forced uni-directional mode.
Next testing round: cups 1.5.3-0ubuntu2~ppa7 is uploaded to my PPA now and this respects uni-directional devices and gives some more messages in error_log.
Please repeat the tests with it (with and without blacklisting usblp) and attach syslog and error_log of the failing tests.
In addition, you can try to force uni-directional mode by
lpadmin -p <queue> -o usb-unidir- default= true
and restore to normal mode via
lpadmin -p <queue> -o usb-unidir- default= false
For <queue> the name of your print queue has to be inserted.
Please repeat your tests with forced uni-directional mode.