[cups.general] Printing from iOS6 -- IPP Read Error

[HaJo Schatz]

On Mon, 2013-03-25 at 10:01 +0100, Till Kamppeter wrote:
> On 03/25/2013 02:56 AM, HaJo Schatz wrote:
> > First my apologies, CUPS 1.3.7 user here, I hope someone has mercy and
> > still bothers to reply to my question even though I guess it'd be
> > super-simple to say "upgrade to 1.6 and you're good"... Well, let me try
> > anyhow:
> > 
> > I recently recognized that my iOS 6 devices can not print to cups/avahi
> > (up2date CentOS 5.9 box, CUPS 1.3.7 as said) while iOS 5 devices work
> > without problem. 
> > (...)
> > However, printing still doesn't work on iOS6. On iOS5 everything still
> > works fine, but on iOS6 it gets aborted with "Error". The only
> > suspicious thing I find in server logs is in /var/log/cups/error_log:
> >  cupsdReadClient: 8 IPP Read Error!
> > 
> > Any idea what that could be and how to fix it; as said, I'd like to try
> > and stay with the distros CUPS version, starting to roll my own RPMs or
> > even installing from source is not really my favorite on a production
> > machine...
> > 
> > Tnx a lot!
> 
> With Ubuntu (Precise 12.04 and newer) as server printing from iOS
> devices works. There I have patched CUPS to do the following things (can
> also be implemented without patching CUPS):
> 
> 1. The DNS-SD sub type "_universal" needs to get added.
> 
> 2. TXT record needs to contain URF=DM3, not URF=none or no URF at all.
> 
> 3. The pdl field of the text record must list at least the input formats:
> 
> application/pdf,image/jpeg,image/urf
> 
> URF is needed here only to identify the device as iOS compatible, the
> other two are the ones in which the actual jobs are sent.
> 
> 4. Set option default fit-to-page or scaling=100 for print queues, so
> that photos get printed on one sheet:
> 
> lpadmin -p <printer> -o scaling-default=100
> 
> The Ubuntu patch also does these two, but they probably server only to
> make (3) working:
> 
> a. The *.convs files must provide a rule to process URF, where the rule
> does not need to actually work, like:
> 
> image/urf  application/pdf  100  -
> 
> b. The *.types files have to provide a rule to detect URF, like:
> 
> image/urf  urf string(0,UNIRAST<00>)
> 
> I had never the iPhone actually sending URF to a Ubuntu server. It seems
> that if the server supports PDF or JPG this gets preferred. I have an
> inkjet which advertises to support URF and JPG, here the iPhone will
> probably send URF for multi-page non-photo jobs.
> 
>    Till
> 

Tnx Till, but the above didn't seem to do the trick:

- Not sure how to implement 1., but I doubt that a DNS-SD sub type
causes an IPP Read error, I'd rather expect browsing problems
- All others are implemented

Seems that your Ubuntu Precise 12.04 uses CUPS 1.5 whereas I am still,
as mentioned, on CUPS 1.3.

Any other suggestion how to solve or at least better debug the IPP Read
error? What's the meaning of "8 IPP Read Error", actually?