Bug 89321

Summary: WARN_ON(!in_irq()) warnings from intel_check_page_flip beginning with 3.19-rc1, kernel flag `threadirqs`
Product: DRI Reporter: Sakari Kapanen <sakari.m.kapanen>
Component: DRM/IntelAssignee: Intel GFX Bugs mailing list <intel-gfx-bugs>
Status: CLOSED FIXED QA Contact: Intel GFX Bugs mailing list <intel-gfx-bugs>
Severity: minor    
Priority: medium CC: intel-gfx-bugs
Version: unspecified   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
dmesg.log which shows the warnings none

Description Sakari Kapanen 2015-02-25 14:06:57 UTC 
Created attachment 113816 [details]
dmesg.log which shows the warnings

This has been discussed in http://lists.freedesktop.org/archives/intel-gfx/2015-February/059291.html , filing it here so it can be better tracked.

Beginning with kernel 3.19-rc1, there are warnings generated by the i915 from the function intel_check_page_flip. A dmesg log from boot to the problem with `drm.debug=13` is attached. This only happens when booting with threaded IRQs enabled by the `threadirqs` kernel flag. 

As pointed out on the mailing lists, this is probably caused because in_irq() only tests for real hardware interrupts, not threaded ones. Further information here: http://lists.freedesktop.org/archives/intel-gfx/2015-February/059623.html

Kernel: 3.19-rc1
Distro: Arch Linux
Machine: Asus Zenbook UX32VD (Intel HD4000 graphics)
Comment 1 Jani Nikula 2015-03-10 17:04:36 UTC 
Fixed by

commit 6c51d46f135b00c00373fcd029786ccef2b02b5b
Author: Dave Gordon <david.s.gordon@intel.com>
Date:   Fri Mar 6 15:34:26 2015 +0000

    drm/i915: use in_interrupt() not in_irq() to check context

in drm-intel-fixes. Thanks for the report.

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