Bug 50243 - [SNB, IVB, VLV, HSW] verify forcewake with additional thread c0 check
Summary: [SNB, IVB, VLV, HSW] verify forcewake with additional thread c0 check
Status: CLOSED FIXED
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Intel (show other bugs)
Version: XOrg git
Hardware: Other All
: medium normal
Assignee: Daniel Vetter
QA Contact:
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2012-05-22 14:43 UTC by Jesse Barnes
Modified: 2017-07-24 23:01 UTC (History)
4 users (show)

See Also:
i915 platform:
i915 features:

Attachments
Bump the CPU to C0 (2.61 KB, patch)
2012-05-29 06:31 UTC, Chris Wilson 		no flags Details | Splinter Review
Bump the CPU to C0 (1.85 KB, patch)
2012-05-29 06:51 UTC, Chris Wilson 		no flags Details | Splinter Review
Implement w/a for sporadic read failures (2.71 KB, patch)
2012-06-13 10:35 UTC, Chris Wilson 		no flags Details | Splinter Review
Show Obsolete (2) View All

Description Jesse Barnes 2012-05-22 14:43:27 UTC 
Need to do the force wake poll then wait for thread C0 before knowing we're out of RC6:

http://dt.igk.intel.com/wa_database/DetailsView/Show?wa_name_id=1141
Comment 1 Chris Wilson 2012-05-29 06:31:03 UTC 
Created attachment 62224 [details] [review]
Bump the CPU to C0

Something like the attached should do the trick.
Comment 2 Chris Wilson 2012-05-29 06:51:49 UTC 
Created attachment 62225 [details] [review]
Bump the CPU to C0
Comment 3 Chris Wilson 2012-06-13 10:35:51 UTC 
Created attachment 62980 [details] [review]
Implement w/a for sporadic read failures
Comment 4 Chris Wilson 2012-07-14 09:31:32 UTC 
commit c4de7b0ffda2bb4843fd7f1052d0a2bb90bd08a5
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Mon Jul 2 11:51:03 2012 -0300

    drm/i915: Implement w/a for sporadic read failures on waking from rc6
    
    As a w/a to prevent reads sporadically returning 0, we need to wait for
    the GT thread to return to TC0 before proceeding to read the registers.
    
    v2: adapt for Haswell changes (Eugeni).
    
    v3: use wait_for_atomic_us for thread status polling.
    
    v3: *really* use wait_for_atomic for polling.
    
Note reveals side-effect bug 51738.

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