Bug 79932

Summary: [HSW/BDW] FBC enabled by default request. FBC massive rework.
Product: DRI Reporter: Guo Jinxian <jinxianx.guo>
Component: DRM/IntelAssignee: Intel GFX Bugs mailing list <intel-gfx-bugs>
Status: CLOSED DUPLICATE QA Contact: Intel GFX Bugs mailing list <intel-gfx-bugs>
Severity: enhancement    
Priority: medium CC: intel-gfx-bugs, przanoni, rodrigo.vivi, yi.sun
Version: unspecified   
Hardware: Other   
OS: All   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
dmesg none

Description Guo Jinxian 2014-06-12 04:00:22 UTC 
Created attachment 100910 [details]
dmesg

==System Environment==
--------------------------
Regression: Yes. 


Non-working platforms: HSW

==kernel==
--------------------------
origin/drm-intel-nightly: 1d3e80d9ff52ecaeecc5b78de32f9bb07ad2231f(fails)
    drm-intel-nightly: 2014y-06m-11d-17h-06m-58s integration manifest
origin/drm-intel-next-queued: 93ec0735decd18e8bdbf8bb9067614f4174ae723(works)
    drm/i915: Fix VLV CRC reading.
origin/drm-intel-fixes: 60671f01a626232532d5b2359bb39ddcce58ec06(fails)
    drm/i915: fix possible refcount leak when resetting forcewake

==Bug detailed description==
-----------------------------
igt/kms_fbc_crc subcases skip

Cases list:
igt/kms_fbc_crc/blt
igt/kms_fbc_crc/context
igt/kms_fbc_crc/mmap_cpu
igt/kms_fbc_crc/mmap_gtt
igt/kms_fbc_crc/page_flip
igt/kms_fbc_crc/page_flip_and_blt
igt/kms_fbc_crc/page_flip_and_context
igt/kms_fbc_crc/page_flip_and_mmap_cpu
igt/kms_fbc_crc/page_flip_and_mmap_gtt
igt/kms_fbc_crc/page_flip_and_render
igt/kms_fbc_crc/render


Output:
./kms_fbc_crc
IGT-Version: 1.7-g4e9df4f (x86_64) (Linux: 3.15.0-rc3_drm-intel-fixes_60671f_20140611+ x86_64)
Test requirement not met in function __real_main487, file kms_fbc_crc.c:513:
Last errno: 0, Success
Test requirement: (!(!strstr(buf, "unsupported by this chipset") && !strstr(buf, "disabled per module param") && !strstr(buf, "disabled per chip default")))
FBC not supported/enabled
Subtest page_flip: SKIP
Subtest mmap_cpu: SKIP
Subtest mmap_gtt: SKIP
Subtest blt: SKIP
Subtest render: SKIP
Subtest context: SKIP
Subtest page_flip_and_mmap_cpu: SKIP
Subtest page_flip_and_mmap_gtt: SKIP
Subtest page_flip_and_blt: SKIP
Subtest page_flip_and_render: SKIP
Subtest page_flip_and_context: SKIP

==Reproduce steps==
---------------------------- 
1. ./kms_fbc_crc

==Bisect results==
----------------------------
Bisect shows: 0368920e51ae0cded0eb518c340a4dd17764d461 is the first bad commit
Author:     Chris Wilson <chris@chris-wilson.co.uk>
AuthorDate: Fri Jun 6 10:37:11 2014 +0100
Commit:     Jani Nikula <jani.nikula@intel.com>
CommitDate: Wed Jun 11 11:06:43 2014 +0300

    drm/i915: Disable FBC by default also on Haswell and later
    
    It causes black screen on bootup and is approximately 100x slower than
    running with FBC disabled, so the GPU runs at a high frequency for much
    longer - completely contrary to the power saving claims. It also still
    has mutex deadlocks in multi-head scenarios, which can lead to a
    system/X lockup. These bugs were known before FBC was enabled by default
    on Haswell and still have not been fixed.
    
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=79716
    Reported-and-tested-by: Jon Kristensen <info@jonkri.com>
    Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
    Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
    Cc: stable@vger.kernel.org
    [Jani: update subject to reflect the actual change]
    Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Comment 1 Chris Wilson 2014-06-12 06:17:36 UTC 
FBC is not supported on that platform.
Comment 2 Chris Wilson 2014-06-13 06:11:47 UTC 
So where is the bug? Features are not tracked here, and you haven't detected a regression, so what is this report for?
Comment 3 Gordon Jin 2014-06-15 13:28:31 UTC 
(In reply to comment #2)
> So where is the bug? Features are not tracked here, and you haven't detected
> a regression, so what is this report for?

FBC should be supported, but is not. That's the defect. (and I think it ok to track expected features in this bugzilla)

I consider this a regression, as it used to work (pass), but not now.
Comment 4 Rodrigo Vivi 2014-10-08 23:43:05 UTC 
FBC is currently disabled by default on all platforms and requires a massive rework to get in a propper stage to get it enabled again.
So, the behaviour on the original report here is the expected so far. It skips when it is disabled by default.
But we can let this entry open as a feature request while we don't get it enabled by default.
Comment 5 Chris Wilson 2015-01-07 18:31:06 UTC 
Forward duping for dependency tracking.

*** This bug has been marked as a duplicate of bug 87704 ***

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