Bug 93037

Summary:	[SKL-Y] DUT does not boot when enabling fbc
Product:	DRI	Reporter:	cprigent <christophe.prigent>
Component:	DRM/Intel	Assignee:	Paulo Zanoni <przanoni>
Status:	CLOSED FIXED	QA Contact:	Intel GFX Bugs mailing list <intel-gfx-bugs>
Severity:	major
Priority:	high	CC:	intel-gfx-bugs, przanoni
Version:	unspecified
Hardware:	x86-64 (AMD64)
OS:	Linux (All)
Whiteboard:
i915 platform:	SKL	i915 features:	display/FBC

Description cprigent 2015-11-20 10:55:47 UTC

Hardware
Platform: SKY LAKE Y A0 QUAL
CPU : Intel(R) Core(TM) M5-6Y54 @ 1.10GHz 4MB (family: 6, model: 78  stepping: 3)
MCP : SKL-Y  D1  
QDF : QJ9W
CPU : SKL D0
Chipset PCH: Sunrise Point LP C1       
CRB : SKY LAKE Y LPDDR3 RVP3 CRB FAB2
Reworks : All Mandatories + FBS02 & FBS03, O-06
Software 
Linux : Ubuntu 15.04 64 bits
BIOS : SKLSE2R1.R00.B104.B01.1511110114
ME FW : 11.0.0.1191
Ksc (EC FW): 1.20
Kernel 4.4.0-rc1 nighlty 0ffc902 from git://anongit.freedesktop.org/drm-intel
  commit 0ffc902f01780eea9bd497435f04883b1c071871
  Author: Daniel Vetter <daniel.vetter@ffwll.ch>
  Date:   Thu Nov 19 17:52:23 2015 +0100
  drm-intel-nightly: 2015y-11m-19d-16h-51m-40s UTC integration manifest
Mesa 11.0.5 from http://cgit.freedesktop.org/mesa/mesa/
xf86-video-intel - 2.99.917 from http://cgit.freedesktop.org/xorg/driver/xf86-video-intel/
Libdrm - 2.4.65 from http://cgit.freedesktop.org/mesa/drm/
Libva - 1.6.1 from http://cgit.freedesktop.org/libva/
vaapi intel-driver - 1.6.1 from http://cgit.freedesktop.org/vaapi/intel-driver
Cairo - 1.14.2 from http://cgit.freedesktop.org/cairo
Xorg Xserver - 1.17.2 from http://cgit.freedesktop.org/xorg/xserver

Steps:
------
1. Boot with kernel boot command lines: i915.disable_power_well=1 i915.enable_fbc=1

Actual result:
--------------
1. DUT does not boot (black screen). No response via ssh.
No log is added to /var/log/kern.log

Expected result:
-----------------
1. DUT boots without problem

Comment 1 Imre Deak 2015-11-20 11:18:00 UTC

Does it make a difference if you boot with i915.disable_power_well=0?

Comment 2 cprigent 2015-11-24 17:13:28 UTC

Bug scrub:
Assigned to Paulo who is working on FBC

Comment 3 Paulo Zanoni 2015-12-07 12:59:08 UTC

I can't reproduce this, but I wonder that maybe one of the recent FBC patches actually fixed it. Can you please confirm with latest drm-intel-nightly?

By the way, was this a regression?

Comment 4 Olivier Berthier 2015-12-18 10:29:06 UTC

Bug not reproduced with latest drm-intel-nightly kernel (6817e96) on Sky Lake Y.

Comment 5 Paulo Zanoni 2015-12-18 12:32:42 UTC

I'm not sure it will be wise to spend more time investigating why the problem happened because FBC is disabled and the problem is gone now, so I'll just close it.

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