Re: DisplayLink compatibility and performance issues

2014-12-02 Thread Sławomir Gonet

Sławomir Gonet sla...@otwiera.cz writes:

 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.

Is there any reason why claiming framebuffer slot cannot be done while
having (another) PCI device already claimed? Also, I have no idea where
Intel driver claims this device - I am not able to find corresponding
code in xf86-driver-intel.

-- 

SG


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DisplayLink compatibility and performance issues

2014-11-30 Thread Sławomir Gonet

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=3v=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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