Bug 85902 - [BSW]igt/pm_rc6_residency/rc6-accuracy sporadically fails
Summary: [BSW]igt/pm_rc6_residency/rc6-accuracy sporadically fails
Status: CLOSED DUPLICATE of bug 76877
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Intel (show other bugs)
Version: unspecified
Hardware: All Linux (All)
: medium normal
Assignee: wendy.wang
QA Contact: Intel GFX Bugs mailing list
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2014-11-05 08:24 UTC by lu hua
Modified: 2017-10-06 14:34 UTC (History)
1 user (show)

See Also:
i915 platform:
i915 features:


Attachments
dmesg (13.98 KB, text/plain)
2014-11-05 08:24 UTC, lu hua
no flags Details

Description lu hua 2014-11-05 08:24:56 UTC
Created attachment 108936 [details]
dmesg

==System Environment==
--------------------------
Regression:  not sure

Non-working platforms: BSW

==kernel==
--------------------------
drm-intel-nightly/f56717bdf29eb7d6a9ec15f095ea2a6858895473

==Bug detailed description==
--------------------------
It sporadically fails on BSW with -nightly kernel, fail rate:1/8.

output:
IGT-Version: 1.8-ge622850 (x86_64) (Linux: 3.18.0-rc3_drm-intel-nightly_f56717_20141105+ x86_64)
The residency counter: 1.000333
Test assertion failure function residency_accuracy, file pm_rc6_residency.c:129:
Failed assertion: (flag_counter != 0) && (counter_result <=1)
Sysfs RC6 residency counter is inaccurate.
Subtest rc6-accuracy: FAIL (0.000s)

==Reproduce steps==
---------------------------- 
1. ./pm_rc6_residency --run-subtest rc6-accuracy
Comment 1 Daniel Vetter 2014-11-25 09:57:40 UTC
Assigning to Wendy since that subtest is from her. From a quick look it makes assumptions about timeouts that don't really hold true always.
Comment 2 wendy.wang 2014-11-27 04:30:03 UTC
BSW RC6 residency accuracy problem is similar as BYT known bug: Bug 76877 - [HSW/BYT]Sysfs RC6 residency counter is inaccurate

Base on Jesse's feedback in bug 76877, also close this bug as will not fix.
"There are a few things going on here:
  - the rc6 residency counters don't have a high precision (some of the data feeding into it is only updated at 1ms intervals)
  - reading from userspace introduces potential error, since the reads may occur further apart than the "time" and "sleep" commands indicate due to scheduling etc.

So I'm closing this as WONTFIX.  We'll have to tolerate some imprecision in these counters.  Since they're for debug only, that should be fine."
Comment 3 Daniel Vetter 2014-11-27 19:11:09 UTC

*** This bug has been marked as a duplicate of bug 76877 ***
Comment 4 Elizabeth 2017-10-06 14:34:05 UTC
Closing old verified.


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