Bug 69920

Summary: [IVB mobile bisected] Direct rendering is not supported when VGA arb is necessary for the device
Product: DRI Reporter: meng <mengmeng.meng>
Component: DRM/IntelAssignee: Ville Syrjala <ville.syrjala>
Status: CLOSED FIXED QA Contact: Intel GFX Bugs mailing list <intel-gfx-bugs>
Severity: blocker    
Priority: highest CC: alex.williamson, intel-gfx-bugs
Version: unspecified   
Hardware: All   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
Xorg.0.log
none
dmesg none

Description meng 2013-09-29 09:39:45 UTC 
Created attachment 86787 [details]
Xorg.0.log

System Environment:       
----------------------------------------------
Platform: IVB mobile bisected
Libdrm:	(master)libdrm-2.4.46-42-gbf4a7cd4b2456d4dc93a86bbcc51eba4ae73390a
Mesa:	(master)b2d5757831e2b67d87d3f80caa7f4ec10fce142b
Xserver:(master)xorg-server-1.14.99.1-215-g7d3d4ae55dd6ee33843
Xf86_video_intel:(master)2.99.902-56-g8ef851b223253c38e6367efdeff6b4d551cd2b6b
Cairo:	(master)38a925460b35c82833dc4d508e7a0e7e84242318
Kernel:	(drm-intel-nightly) 92e1fa095163afb89cb79f491711e4b249ced68a

Bug detailed description:
----------------------------------------------
Direct rendering is not supported when VGA arb is necessary for the device on IVB mobile.The problem doesn't exist on IVB desktop and other platform. Please see Xrog.0.Log, dmesg.log attached.

It’s Kernel -dinq regression, bisecting show that the first bad commit is:
81b5c7bc8de3e6f63419139c2fc91bf81dea8a7d is the first bad commit
commit 81b5c7bc8de3e6f63419139c2fc91bf81dea8a7d
Author: Alex Williamson <alex.williamson@redhat.com>
Date:   Wed Aug 28 09:39:08 2013 -0600

    i915: Update VGA arbiter support for newer devices

Reproduce steps:
---------------------------------------------
1, xinit&
2, check Xrog.0.Log
Comment 1 meng 2013-09-29 09:40:07 UTC 
Created attachment 86788 [details]
dmesg
Comment 2 meng 2013-09-29 09:43:08 UTC 
Due this problem, this IVB mobile would use swrast_dri.so in place of i965_dri.so.
Comment 3 Chris Wilson 2013-09-29 09:57:18 UTC 
Note this impacts all users of discrete GPU with Core processors.

Ville is working on some patches; I keep complaining as my gm45 lockups with said patches and opening the lid.
Comment 4 Chris Wilson 2013-10-17 10:47:10 UTC 
commit ebff5fa9d545574324095d9c6a3cb80c9157abc5
Author: Dave Airlie <airlied@redhat.com>
Date:   Fri Oct 11 15:12:04 2013 +1000

    Revert "i915: Update VGA arbiter support for newer devices"
    
    This reverts commit 81b5c7bc8de3e6f63419139c2fc91bf81dea8a7d.
Comment 5 meng 2013-10-21 02:01:17 UTC 
Verifed it.
Comment 6 Jari Tahvanainen 2016-10-07 05:45:22 UTC 
Closing verified+fixed.

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