Bug 79616

Summary:	L4D2 crash on startup
Product:	Mesa	Reporter:	Tapani Pälli <lemody>
Component:	Drivers/DRI/i965	Assignee:	Tapani Pälli <lemody>
Status:	RESOLVED FIXED	QA Contact:	Intel 3D Bugs Mailing List <intel-3d-bugs>
Severity:	normal
Priority:	medium	CC:	idr, mattst88
Version:	git
Hardware:	Other
OS:	All
Whiteboard:
i915 platform:		i915 features:
Attachments:	hopeful fix

Description Tapani Pälli 2014-06-04 05:07:20 UTC

L4D2 crashes with current Mesa master, I'm getting:

---- 8< ---
hl2_linux: intel_mipmap_tree.c:1881: intel_miptree_map_movntdqa: Assertion `(((uintptr_t) map->ptr) & 15) == misalignment' failed.
---- 8< ---

I bisected this to the following commit:

commit f935dfc022f2481b3ed6ecfccafef37ce71776f0
Author: Matt Atwood <matthew.s.atwood@intel.com>
Date:   Fri May 2 09:44:45 2014 -0700

    i965: Use SSE4.1 runtime detection for intel_miptree_map.
    
    Previous it was a compile-time decision.
    
    Reviewed-by: Matt Turner <mattst88@gmail.com>

Comment 1 Tapani Pälli 2014-06-04 05:11:19 UTC

Reproduced this on IVB ultrabook and HSW brixbox.

Comment 2 Tapani Pälli 2014-06-04 07:17:16 UTC

Created attachment 100388 [details] [review]
hopeful fix

this fixes the issue for me, I'd like Matt to verify if this fix is correct.

Comment 3 Ian Romanick 2014-06-04 16:16:55 UTC

I think that patch is correct.  It seems like it's just luck that malloc works at all.  I don't think there's any guarantee that it will provide better than sizeof(void*) alignment.  For allocations smaller than sizeof(void*), it won't even do that.  Consider that my Reviewed-by.

I'd still wait to hear from Matt.

Comment 4 Tapani Pälli 2014-06-05 06:02:54 UTC

pushed to master

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