printing via serial to usb cable

[Wade Smart]

Wade Smart wrote:
> Rashkae wrote:
>> Wade Smart wrote:
>>> Rashkae wrote:
>>>> Wade Smart wrote:
>>>>> 20090128 0906 GMT-5
>>>>>
>>>>> I recently posted about my parallel to usb cable causing lots of 
>>>>> problems on my system - and since I received no help there I 
>>>>> decided to try something else.
>>>>>
>>>>> I borrowed a serial to usb cable. I was able to print a test page by:
>>>>> sudo echo "Printer Test" > /dev/ttyUSB0
>>>>>
>>>>> but I havent been able to print any other way.
>>>>>
>>>>> In cups I changed the uri to usb://dev/ttyUSB0 and then I ran the 
>>>>> configure script but nothing changed.
>>>>>
>>>>> What else can I try?
>>>>>
>>>>> Wade
>>>>>
>>>> Try a serial URI
>>>>
>>>> ex: serial:/dev/ttyUSB0?baud=11500
>>>>
>>>> Also note: I think (without being absolutely certain) that you only use
>>>> 1 / when you refer to a file (or a device note) directly on your 
>>>> system,
>>>> use // when your are specifying a network resource.  I don't know if
>>>> that matters or if CUPS is smart enough to figure that out on it's own.
>>>>  ( // also seems to be used by USB printers that are named by their
>>>> model number rather than a device note, for examply, in my system, I
>>>> have usb://Samsung/ML-1740  compared to parallel:/dev/lp0)
>>>>
>>> 20090128 1007 GMT-5
>>>
>>> Okay... LaserJet4050 (Default Printer) "Unable to open device file 
>>> "/dev/ttyUSB0": Permission denied"
>>>
>>> And in my logs:
>>> Jan 28 10:05:42 wadesmart kernel: [145933.655140] 
>>> audit(1233158742.764:27): type=1503 operation="inode_permission" 
>>> requested_mask="rw::" denied_mask="rw::" name="/dev/ttyUSB0" 
>>> pid=28751 profile="/usr/sbin/cupsd" namespace="default"
>>>
>>> Jan 28 10:05:43 wadesmart kernel: [145934.058182] 
>>> audit(1233158743.168:28): type=1503 operation="inode_permission" 
>>> requested_mask="::rw" denied_mask="::rw" name="/dev/tty" pid=28757 
>>> profile="/usr/sbin/cupsd" namespace="default"
>>>
>>> Jan 28 10:06:26 wadesmart kernel: [145977.419281] 
>>> audit(1233158786.616:29): type=1503 operation="inode_permission" 
>>> requested_mask="rw::" denied_mask="rw::" name="/dev/ttyUSB0" 
>>> pid=28801 profile="/usr/sbin/cupsd" namespace="default"
>>>
>>> Jan 28 10:06:27 wadesmart kernel: [145977.820661] 
>>> audit(1233158787.020:30): type=1503 operation="inode_permission" 
>>> requested_mask="::rw" denied_mask="::rw" name="/dev/tty" pid=28808 
>>> profile="/usr/sbin/cupsd" namespace="default"
>>>
>>> Wade
>>
>> By default, Ubuntu gives read/write permission to User root and group lp
>> for printer devices.
>>
>> Unfortunately, the device scripts probably don't realize your serial
>> device is supposed to be a printer device, and therefore lp group (which
>> cups user is probably using) doesn't have write permission.
>>
>> You can test with the following:
>>
>> first, make sure that the device is not a symlink to somewhere else.
>>
>> ls -lh /dev/ttyUSB0
>>
>> then, assuming we have the correct device file:
>>
>> sudo chown root:lp /dev/ttyUSB0
>>
>> sudo chmod 660 /dev/ttyUSB0
>>
>>
>> Then try printing again and let us know if it works.  Unfortunately,
>> making these changes permanent requires a bit more voodoo.. Hopefully
>> someone can step in, else I'll research it further.
>>
>> PS: Karl has a well known habit on this list to jump in to topics way
>> over his head to either hilarious or catastrophic result.  I suggest
>> liberal use of salt grains.
>>
> 
> 20090128 1200 GMT-5
> 
> I did the above and I have the following:
> 
> logs:
> Xorg.0.log: (WW) Open ACPI failed (/var/run/acpid.socket) (Connection 
> refused)
> 
> Message:
> Jan 28 11:59:37 wadesmart kernel: [152755.014555] 
> audit(1233165577.832:39): type=1503 operation="inode_permission" 
> requested_mask="rw::" denied_mask="rw::" name="/dev/ttyUSB0" pid=1745 
> profile="/usr/sbin/cupsd" namespace="default"
> 
> Jan 28 11:59:37 wadesmart kernel: [152755.144901] 
> audit(1233165577.964:40): type=1503 operation="inode_permission" 
> requested_mask="::rw" denied_mask="::rw" name="/dev/tty" pid=1752 
> profile="/usr/sbin/cupsd" namespace="default"
> 
> restarted cups and this is on the Printers page after refreshing:
> LaserJet4050 (Default Printer) "Unable to open device file 
> "/dev/ttyUSB0": Permission denied"
> 
> Wade
> 

Just for fun I changed the serial://dev... back to usb://dev... and I 
received this message:

Jan 28 12:08:52 wadesmart kernel: [153308.357183] 
audit(1233166132.288:46): type=1503 operation="inode_permission" 
requested_mask="a::" denied_mask="a::" name="/dev/tty" pid=2619 
profile="/usr/sbin/cupsd" namespace="default"

So far its been denied_mask="rw:: or ::rw but now ts =a::.

Wade
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