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Date: Mon, 11 Nov 2013 13:14:48 GMT
From: Tamas Szakaly <sghctoma@gmail.com>
To: freebsd-gnats-submit@FreeBSD.org
Subject: Suspend fails on Lenovo Thinkpad x220 when RC6 power saving is enabled.
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>Number:         183859
>Category:       kern
>Synopsis:       [suspend/resume] Suspend fails on Lenovo Thinkpad x220 when RC6 power saving is enabled.
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Nov 11 13:20:01 UTC 2013
>Closed-Date:    
>Last-Modified:  Tue Apr 22 05:35:20 UTC 2014
>Originator:     Tamas Szakaly
>Release:        9.2-RELEASE
>Organization:
>Environment:
FreeBSD test 9.2-RELEASE FreeBSD 9.2-RELEASE #2: Mon Oct 28 19:19:09 UTC 2013     root@test:/usr/obj/usr/src/sys/GENERIC  amd64
>Description:
Suspend fails when RC6 power saving feature of the i915 is enabled. The display turns off, but the system never goes to S3: it is possible to access it via SSH. This happens with all three RC6 levels (RC6, RC6p and RC6pp).

Based on some debugging it seems that the suspend is prevented because "gen6_pm_rps_work_func" (@sys/dev/drm2/i915/i915_irq.c) hangs on a "DRM_LOCK(dev)" call, thus the "taskqueue_drain(dev_priv->tq, &dev_priv->rps_task);" call in ironlake_irq_uninstall (@sys/dev/drm2/i915/i915_irq.c) can never finish.
>How-To-Repeat:
1. Enable RC6 in /boot/loader.conf:
    drm.i915.enable_rc6=1 # or 3 for RC6p, 7 for RC6pp
2. With RC6 enabled, try to suspend the machine:
    acpiconf -s3

>Fix:


>Release-Note:
>Audit-Trail:
Responsible-Changed-From-To: gnats-admin->freebsd-bugs 
Responsible-Changed-By: linimon 
Responsible-Changed-When: Tue Nov 12 02:53:11 UTC 2013 
Responsible-Changed-Why:  
reclassify. 

http://www.freebsd.org/cgi/query-pr.cgi?pr=183859 
>Unformatted:
