Bug 9680

Summary: SDVO-Card + DVI-Port + modesetting branch + 1680px-screen result in bogus resolution
Product: xorg Reporter: Johannes Truschnigg <johannes.truschnigg>
Component: Driver/intelAssignee: Eric Anholt <eric>
Status: RESOLVED FIXED QA Contact:
Severity: normal    
Priority: high CC: dcm
Version: git   
Hardware: x86 (IA32)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
Workaround none

Description Johannes Truschnigg 2007-01-16 12:17:20 UTC 
I am running Gentoo ~amd64 (X Window System Version 7.1.1) on a sytem sporting 
an Intel G965 onboard Graphics adpter. I use a Sil164-based SDVO Card for 
digital output to my iiyama 2200WS TFT display, which has a native resolution 
of 1680x1050. Using the modesetting driver from git, this works as long as I 
use the _analog_ D-SUB-out of the adapter; switching to DVI-D results in the 
resolution ending up in 1736x1050, which looks pretty weird.

I already posted this at the xorg mailing lists, and was advised to create a 
bug report, as I've been the second guy pointing out this particular issue.

X's logfile may be found at http://gnulords.org/~colo/tmp/Xorg.0.log
X's configfile may be found at http://gnulords.org/~colo/tmp/xorg.conf

If I am supposed to provide any other info to have this resolved, please don't 
hesitate to contact me.
Comment 1 Johannes Truschnigg 2007-01-16 12:29:57 UTC 
It's me again - since DRI started to work again with the driver version I 
checked out today, I tried starting ioquake3 with software rendering forced 
(since my version of Mesa is too old for hardware-accelerated GLX to make the 
cut), and after quitting the game, I'm back at a perfect 1680x1050px-desktop 
and quite happy with it.
I could imagine that info might come in handy when tracking that weird issue 
down.

Cheers!
Comment 2 David Moore 2007-01-27 11:19:10 UTC 
This bug occurs for me also.  I have a Intel DG965WH motherboard and I'm using a Wintec-branded SDVO card and its DVI output.  My monitor is a Dell 2000FP with a native resolution of 1600x1200.  When I start X with the mode setting branch, my monitor reports that it is being fed at 1656x1200.  The desktop itself is still exactly 1600x1200, but is left-justified and squished slightly into the 1656x1200 mode.

I will attach a patch that works around the problem for me.
Comment 3 David Moore 2007-01-27 11:22:28 UTC 
Created attachment 8517 [details] [review]
Workaround

This patch avoids the problem by eliminating the mysterious requirement "H Blanking size must be < 63*8".  Presumably that requirement is in there for a reason, but it is incompatable with a lot of high resolution modelines.

If I simply remove the test, it "works for me".
Comment 4 Johannes Truschnigg 2007-01-27 12:07:24 UTC 
Yeah, great stuff - works for me too.

My rather strange "workaround" (starting an OpenGL application fullscreen, making it switch resolutions, and get back to my desktop with proper 1680x1050) ceased to work about two days ago after updating the driver once more, alongside breaking DRI, by the way.
Comment 5 Tristan Willy 2007-01-28 14:41:12 UTC 
David Moore's patch fixes the issue for me.

- Tristan
Comment 6 Eric Anholt 2007-01-29 09:56:22 UTC 
Committed an even more aggressive version of this patch, which ajax and I had talked about on IRC a while back.  Thanks!

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