--- Begin Message ---
- To: Debian Bug Tracking System <submit@bugs.debian.org>
- Subject: cups: pxlmono fails to print on Samsung ML-2250 with 9.28rc
- From: Johannes Stezenbach <js@sig21.net>
- Date: Sun, 6 Oct 2019 21:27:36 +0200
- Message-id: <20191006192736.GA16498@sig21.net>
Package: ghostscript
Version: 9.28~~rc4~dfsg-1
Severity: important
Tags: upstream
Dear Maintainer,
my Samsung ML-2250 printer stopped to work, it outputs a page with
this error message:
PCL6 ERROR - sb_count != -128
POSITION : 0xbc8 (3016)
SYSTEM : XLPGP/xl_pattern
LINE : 890
VERSION : PCL6 3.34 05-01-2004
It took me a while to figure out what part of the printing system
caused the failure, but after downgrading ghostscript to
9.27~dfsg-3.1 printing worked again.
For fun I decided to dig into it:
- I used "gs -sDEVICE=pxlmono -sOutputFile=t.raw -r300x300 foo.pdf"
to generate output for 9.27 and 9.28
- I used ghostpdl/pcl/tools/pxldis.py tool from ghostscript
source to convert it to something readable and compared it
-> the only difference is the use of RLE compression with 9.28
- I checked the RLE encoding and it is correct
(pcl_xl_2_0_technical_reference_rev2_2.pdf appendix Q)
Then it dawned on me that ghostscript's 0x80 "EOD" marker
is rejected by the Samsung printer firmware.
Ghostscript adds the (apparently useless, at least for PCL6)
EOD marker as the last byte of RLE compressed data. According to
spec, 0x80 bytes have no meaning and should be ignored
("A control byte of -128 is ignored and is not included in the
decompressed data. The byte following a control byte of 128 is
treated as the next control byte."). But the error message from
my printer reads like a failed assertion for this case, i.e. the
printer firmware is buggy.
To test my theory I made the following change:
--- ghostscript-9.28~~rc4~dfsg.orig/base/srle.c
+++ ghostscript-9.28~~rc4~dfsg/base/srle.c
@@ -329,11 +329,13 @@ run_len_0_n0_read:
*++q = n0;
}
case state_eod_unmarked:
+#if 0
if (wlimit - q < 1) {
ss->state = state_eod_unmarked;
goto no_output_room;
}
*++q = 128; /* EOD */
+#endif
case state_eod:
ss->run_len = 0;
ss->state = state_0;
Success! It make my printer work again.
Best Regards,
Johannes
-- System Information:
Debian Release: bullseye/sid
APT prefers unstable
APT policy: (500, 'unstable'), (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386
Kernel: Linux 5.2.15 (SMP w/4 CPU cores; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=de_DE.utf-8 (charmap=UTF-8), LANGUAGE=en_US:en (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: sysvinit (via /sbin/init)
Versions of packages ghostscript depends on:
ii libc6 2.29-2
ii libgs9 9.28~~rc4~dfsg-1
ghostscript recommends no packages.
Versions of packages ghostscript suggests:
ii ghostscript-x 9.28~~rc4~dfsg-1
-- no debconf information
--- End Message ---
--- Begin Message ---
- To: 941864-close@bugs.debian.org
- Subject: Bug#941864: fixed in ghostscript 9.50~dfsg-5
- From: Jonas Smedegaard <dr@jones.dk>
- Date: Wed, 27 Nov 2019 19:35:39 +0000
- Message-id: <E1ia36B-0009ZJ-JN@fasolo.debian.org>
Source: ghostscript
Source-Version: 9.50~dfsg-5
We believe that the bug you reported is fixed in the latest version of
ghostscript, which is due to be installed in the Debian FTP archive.
A summary of the changes between this version and the previous one is
attached.
Thank you for reporting the bug, which will now be closed. If you
have further comments please address them to 941864@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.
Debian distribution maintenance software
pp.
Jonas Smedegaard <dr@jones.dk> (supplier of updated ghostscript package)
(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512
Format: 1.8
Date: Wed, 27 Nov 2019 20:15:08 +0100
Source: ghostscript
Architecture: source
Version: 9.50~dfsg-5
Distribution: unstable
Urgency: medium
Maintainer: Debian Printing Team <debian-printing@lists.debian.org>
Changed-By: Jonas Smedegaard <dr@jones.dk>
Closes: 941864
Changes:
ghostscript (9.50~dfsg-5) unstable; urgency=medium
.
* add patch cherry-picked upstream
to add 'omitEOD' flag to RLE compressor and use for PXL;
closes: bug#941864,
thanks to Agustin Martin and Johannes Stezenbach
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