Bug 976

Summary:	driver compatibilty broken again ...
Product:	xorg	Reporter:	Stefan Dirsch <sndirsch>
Component:	Server/General	Assignee:	Xorg Project Team <xorg-team>
Status:	RESOLVED FIXED	QA Contact:
Severity:	major
Priority:	high	CC:	eich, eta, keithp, kem
Version:	git
Hardware:	All
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:
Bug Depends on:
Bug Blocks:	351

Description Stefan Dirsch 2004-08-03 13:07:58 UTC

Looks like graphics driver binary compatibility has been broken again. :-( 
 
When trying to load the nvidia driver I get: 
 
Program received signal SIGSEGV, Segmentation fault. 
0x080d16f3 in CreateConnectionBlock () 
(gdb) #0  0x080d16f3 in CreateConnectionBlock () 
#1  0x080d1d19 in main () 
(gdb)  
 
This is CVS Head by today (2004-08-03, 18:28 CET). When using a Xorg Server 
built from CVS Head by sunday (2004-08-01, 2:00 CET) this problem does not 
happen. So it's quite new ...

Comment 1 Stefan Dirsch 2004-08-03 13:16:53 UTC

*** Bug 977 has been marked as a duplicate of this bug. ***

Comment 2 Eric Anholt 2004-08-03 16:29:51 UTC

I'm assuming Composite caused this to happen, by the driver stomping on some
memory somewhere due to structure changes.  Could you check to be sure that if
you add
#define BuildComposite NO
to your host.def, it goes away?

Comment 3 Stefan Dirsch 2004-08-03 17:58:13 UTC

Thanks for the hint. I'll give it a try and let you know.

Comment 4 Stefan Dirsch 2004-08-03 19:28:39 UTC

Yes, disabling build of Composite fixes the problem. nvidia driver now works 
again. Hmm ...

Comment 5 Kevin E. Martin 2004-08-06 11:57:07 UTC

Someone needs to track this one down as maintaining ABI compatibility is one of
the goals for this release.

My only thought currently is the two extra fields in the VisualRec structure for
alphaMask and offsetAlpha might be causing the problem, but I haven't looked
very far into this yet.

Comment 6 Kevin E. Martin 2004-08-06 11:58:16 UTC

Adding Keith Packard and Eric Anholt on the CC list for their comments.

Comment 7 Keith Packard 2004-08-06 19:33:12 UTC

I removed the new fields in the Visual structure related to making core color
allocation automatically set alpha bits in returned pixel values.

Aside from the new screen_x/screen_y fields in pixmaps (which we hope aren't an
ABI issue), there shouldn't be any other ABI changes controlled by building with
COMPOSITE defined.

Comment 8 Stefan Dirsch 2004-08-06 19:38:16 UTC

Thanks, Keith! I'll give it a try ASAP (this weekend for sure) and let you 
know about the results.

Comment 9 Stefan Dirsch 2004-08-07 01:25:24 UTC

Just verified. The nvidia driver works fine again. :-)

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