pkg/45979: pkgsrc/graphics/xli creatively mangles bitmaps

["Bernhard Riedel" <bernhard%sdg.de@localhost>]

>Number:         45979
>Category:       pkg
>Synopsis:       xli-1.17.0nb11 shows psychedelic artifacts when trying to 
>display 1-bit deep pictures while using MIT-SHM
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Feb 10 21:30:00 +0000 2012
>Originator:     Bernhard "Burnhard" Riedel
>Release:        NetBSD 5.1
>Organization:
a nice concept
>Environment:
System: NetBSD wip.crg.de 5.1 NetBSD 5.1 (WIP) #0: Sun Nov 27 22:39:05 CET 2011 
root%wip.crg.de@localhost:/sdata/usr/src/sys/arch/amd64/compile/WIP amd64
Architecture: x86_64
Machine: amd64
>Description:
        xli-1.17.0nb11 (from pkgsrc/graphics/xli) produces weird and beautiful
        effects when trying to display 1 bit deep bitmaps.
        This doesn't seem to depend on the file format (tried with .pbm and 
.png)
>How-To-Repeat:
        (a) bitmap > screen
            get http://bernhard.at.shangtai.net/PR/PR-20120209a-xli/Tea1.png
            xli Tea1.png
            you might notice that 
              the picture contents are warped
              there are colour effects
              xli might render pixels outside the window frame on the left
              more weirdness appears when trying to drag the viewable area 
around
        (b) small bitmap
            get http://bernhard.at.shangtai.net/PR/PR-20120209a-xli/draw02.png
            xli draw02.png
            the picture will be shown correctly.
            now press a few keys. "l"/"r" to rotate, "." to reload.
>Fix:
        disable MIT-SHM extension (see xorg.conf(5))
          or
        run xli and Xorg on two different machines

>PS:
        I want to thank many people who helped reproduce/isolate this 
phenomenon,
        especially Ignatios Souvatzis (for pointing out SHM as an important 
difference
        between running on local vs remote display) and Matthias Kretschmer.
        Finally, Staffan Thomén tried with pkgsrc xli on Irix, and it worked
        correctly, despite MIT-SHM in his Xserver.
        Can't isolate which one of the differences (Irix X11 vs Xorg, different 
CPU
        endianness, different framebuffer endianness) is responsible.

>Unformatted:
                NetBSD wip.crg.de 5.1 NetBSD 5.1 (WIP) #0: Sun Nov 27 22:39:05 
CET 2011  root%wip.crg.de@localhost:/sdata/usr/src/sys/arch/amd64/compile/WIP 
amd64
                NetBSD yuri.crg.de 5.1.1 NetBSD 5.1.1 (YURI) #0: Sat Feb  4 
09:20:13 CET 2012  
root%yuri.crg.de@localhost:/sdata/standard/usr/src/sys/arch/i386/compile/YURI 
i386
                 unspecified FreeBSD
                unspecified Linux