Bug 89737

Summary: [HSW Regression 3.19.2]igt/drm_read/short-buffer-block fails
Product: DRI Reporter: lu hua <huax.lu>
Component: DRM/IntelAssignee: Intel GFX Bugs mailing list <intel-gfx-bugs>
Status: CLOSED INVALID QA Contact: Intel GFX Bugs mailing list <intel-gfx-bugs>
Severity: normal    
Priority: high CC: christophe.prigent, intel-gfx-bugs, przanoni
Version: unspecified   
Hardware: All   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
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Description lu hua 2015-03-24 02:26:58 UTC 
Created attachment 114567 [details]
dmesg

==System Environment==
--------------------------
Regression: Yes
it fails on 3.19.2, works well 3.18.0

Non-working platforms: HSW

==kernel==
--------------------------
commit 660613d1a4e94144490850b6c3d350331860fac4
Author: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date:   Wed Mar 18 14:11:52 2015 +0100

    Linux 3.19.2

==Bug detailed description==
-----------------------------
It fails on 3.19.2, works well 3.18.0 and the latest drm-intel-nightly kernel.
igt@drm_read@short-buffer-nonblock also fails.

output:
IGT-Version: 1.10-ge7d26df (x86_64) (Linux: 3.19.2_v3.19.2+ x86_64)
Test assertion failure function test_short_buffer, file drm_read.c:148:
Failed assertion: read(fd, buffer, 4) == 0
Last errno: 11, Resource temporarily unavailable
error: -1 != 0
Subtest short-buffer-block failed.
**** DEBUG ****
Test assertion failure function test_short_buffer, file drm_read.c:148:
Failed assertion: read(fd, buffer, 4) == 0
Last errno: 11, Resource temporarily unavailable
error: -1 != 0
****  END  ****
Subtest short-buffer-block: FAIL (0.000s)

Reproduce steps:
-------------------------
1. ./drm_read --run-subtest short-buffer-block
Comment 1 Jesse Barnes 2015-08-04 17:54:39 UTC 
The drm_read routine will return EAGAIN if the event list is empty, so this may be expected behavior if the event hasn't been queued yet.  Could be a test bug or a race in the event delivery code in the kernel.
Comment 2 Paulo Zanoni 2015-08-04 20:03:05 UTC 
Hi

Is this still happening on the 3.19 series? What about -nightly? Is this really HSW-specific?

Thanks,
Paulo
Comment 3 Paulo Zanoni 2015-08-04 20:18:34 UTC 
(In reply to Paulo Zanoni from comment #2)
> Hi
> 
> Is this still happening on the 3.19 series? What about -nightly? Is this
> really HSW-specific?

Hmm, I can reproduce this on Ubuntu's 3.19.0-23 Kernel, but not on -nightly.
Comment 4 Chris Wilson 2015-08-05 08:07:31 UTC 
I have no idea why they thought 3.18 worked, since the test was designed to expose the bugs in the read routine since its introduction.

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