Bug 29820 - Nouveau doesn't handle VGA-OUT correctly on a 9400M (Macbook Unibody), but DVI-OUT works !?!?!
Summary: Nouveau doesn't handle VGA-OUT correctly on a 9400M (Macbook Unibody), but DV...
Status: RESOLVED INVALID
Alias: None
Product: xorg
Classification: Unclassified
Component: Driver/nouveau (show other bugs)
Version: unspecified
Hardware: x86-64 (AMD64) Linux (All)
: medium normal
Assignee: Nouveau Project
QA Contact: Xorg Project Team
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2010-08-26 06:55 UTC by Bill Yerazunis
Modified: 2013-08-18 18:10 UTC (History)
1 user (show)

See Also:
i915 platform:
i915 features:

Attachments

Description Bill Yerazunis 2010-08-26 06:55:59 UTC 
On the Macbooks there are two display adapters you can plug into the 
Mini DisplayPort socket- one yields DVI, the other VGA.

DVI output works fine on all monitors tested.  Yeah team!

VGA does not.  Although Linux sees the external display and gets the external monitor information correctly (i.e. EDID seems to work), but the VGA signal
generated is only non-syncing artifacts; different monitors show different  
results, but none succeed in syncing up to what should be reasonable 
resolutions and frame rates.

There is no relevant results on this in the Xorg.0.log file, so no attachments.

The machine is a late 2008 Macbook Unibody (5,1) running Fedora Core 13, but
the same behavior is seen on Core 11 and Ubuntu, and booting via ReFIT.  

It's not a broken-hardware problem; both the ->VGA and ->DVI adapters work fine
when booted into MacOS.
Comment 1 saintger 2010-08-26 13:52:52 UTC 
I've opened a similar bug on this subject:
https://bugs.freedesktop.org/show_bug.cgi?id=29415

I think they are duplicates but not sure...
Comment 2 Ben Skeggs 2010-08-26 15:28:48 UTC 
This isn't an issue with VGA out, your macbook doesn't *do* VGA at all.  DP->DVI works because the adaptor is passive, and the display looks basically like normal DVI to the driver.  VGA on the other hand is an active adaptor, and nouveau sees a DisplayPort monitor, not VGA.

Nouveau DP support is currently limited to working only when the VBIOS (or, EFI) has initialised the display previously.  If it hasn't been, a blank screen (or possibly badly synced screen sometimes) is the expected result.
Comment 3 Yuriy Khomchik 2010-09-12 14:46:12 UTC 
See also similar bug 29714. In this case, corrupted image is displayed on a laptop screen via embedded DisplayPort (eDP).
Comment 4 Ilia Mirkin 2013-08-18 18:10:42 UTC 
It appears that this bug report has laid dormant for quite a while. Sorry we haven't gotten to it. Since we fix bugs all the time, chances are pretty good that your issue has been fixed with the latest software. Please give it a shot. (Linux kernel 3.10.7, xf86-video-nouveau 1.0.9, mesa 9.1.6, or their git versions.) If upgrading to the latest isn't an option for you, your distro's bugzilla is probably the right destination for your bug report.

In an effort to clean up our bug list, we're pre-emptively closing all bugs that haven't seen updates since 2011. If the original issue remains, please make sure to provide fresh info, see http://nouveau.freedesktop.org/wiki/Bugs/ for what we need to see, and re-open this one.

Thanks,

The Nouveau Team

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