Hi everyone,

I've recently bought DisplayLink device[1]. According to [2], it
might/should work under OpenBSD so I gived it a try. My results are:

1) Not detected USB PID - I've added it as new device to kernel's udl
   driver.
2) Conflict with bulit-in Intel HD graphics card.
   I spent some time debugging why xf86-video-wsudl is not detecting my
   DL-165 adapter. After downloading xenocara I was debugging wsudl and
   what I found:
   
   WsudlProbe():
   driver/xf86-video-wsudl/src/wsudl_driver.c:309 calls "xf86ClaimFbSlot()"

   xf86ClaimFbSlot()
   xserver/hw/xfree86/common/xf86fbBus.c:62 checks if pciSlotClaimed is
   true.

   And, unfortunately, on my platform pciSlotClaimed == 1, because of
   intel driver. However, things started to work when before calling
   xf86ClaimFbSlot() I've set pciSlotClaimed to 0.
3) UDL device does not get auto-detected
   I had to define UDL device manually in xorg.conf and connect screens
   using Xinerama to make it working
4) Resolution problems with Intel - maybe because of hacking from point
   2 in random situations intel driver fails and messes up resolution on
   one of the screens - about 3/4 of screen become "unusable". No idea
   how to explain it.
5) Performance
   What I've found: [3] - so more or less "It will not work, no
   way". But under Linux there are no performance issues at all. I can
   even play video (but not in fullscreen), 1080p works great. Where's
   the bottleneck in OpenBSD? I am not even able to move window on the
   desktop smoothly, in idle Xorg process consumes 5-10% of CPU with
   peaks up to 40%.

Further informations about my platform:
- Lenovo ThinkPad t420s with Intel i7.
- 2× BENQ G2420HD
- i-tec 2.0 TRIO USB to DVI (DisplayLink DL-165 inside)

Unfortunately, I am really newbie in both OpenBSD and kernel
development, so I am afraid that debugging like this is everything I am
able to. Are there any active developers of wsudl driver? Issues 4 and 5
are fatal to me, I need two displays - do you have any ideas how to move
things forward here?

Regards,
Slawek


[1] - http://www.i-tec-europe.eu/?t=3&v=130
[2] - http://libdlo.freedesktop.org/wiki/
[3] - 
http://openbsd.7691.n7.nabble.com/Xorg-wsudl-4-DL-165-consumes-a-lot-of-cpu-td224195.html

-- 

SG

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