Comment 0 for bug 1351014

SRU Justification:

Impact: Kernel warning every boot making it seem like the system is faulty but it is harmless. This only applies to i915_bdw, and is impacting certification on some prerelease machines.
Fix: Upstream increased the timeout required to hit it so it will not affect the machines we have anymore in 3.14, and also demoted it from a warning to DRM_INFO_ONCE.
Testcase: Boot trusty on an affected broadwell machine, check dmesg for warning

[Results]
Expected: There should be no WARNING messages for i915_bdw.
Actual: This warning is displayed

[ 13.157688] ------------[ cut here ]------------
[ 13.157726] WARNING: CPU: 3 PID: 395 at /build/buildd/linux-3.13.0/ubuntu/i915/intel_opregion.c:266 swsci+0x2ec/0x300 [i915_bdw]()
[ 13.157729] excessive driver sleep timeout (DSPL) 1000
[ 13.157732] Modules linked in: crct10dif_pclmul(+) lib80211_crypt_tkip crc32_pclmul ghash_clmulni_intel aesni_intel snd_hda_intel(OF+) snd_hda_controller(OF) aes_x86_64 snd_hda_codec(OF) snd_hwdep lrw gf128mul snd_pcm glue_helper ablk_helper cryptd wl(POF+) lib80211 snd_seq_midi snd_seq_midi_event cfg80211 snd_rawmidi serio_raw i915_bdw(+) snd_seq snd_page_alloc snd_seq_device snd_timer lpc_ich mei_me mei snd soundcore drm_kms_helper drm i2c_algo_bit parport_pc ppdev mac_hid acpi_pad lp parport btrfs xor raid6_pq libcrc32c dm_mirror dm_region_hash dm_log usbhid hid ahci libahci wmi video
[ 13.157779] CPU: 3 PID: 395 Comm: systemd-udevd Tainted: PF O 3.13.0-32-generic #57-Ubuntu
[ 13.157783] Hardware name: Dell Inc. FOOBAR, BIOS R21 07/17/2014
[ 13.157785] 0000000000000009 ffff880156921818 ffffffff8171bcb4 ffff880156921860
[ 13.157790] ffff880156921850 ffffffff810676cd ffffc900106a0218 ffff88003598d800
[ 13.157794] 00000000000001f4 0000000000000008 ffff880156921928 ffff8801569218b0
[ 13.157799] Call Trace:
[ 13.157807] [<ffffffff8171bcb4>] dump_stack+0x45/0x56
[ 13.157812] [<ffffffff810676cd>] warn_slowpath_common+0x7d/0xa0
[ 13.157815] [<ffffffff8106773c>] warn_slowpath_fmt+0x4c/0x50
[ 13.157847] [<ffffffffa02bc21c>] swsci+0x2ec/0x300 [i915_bdw]
[ 13.157870] [<ffffffffa02bd044>] intel_opregion_setup+0x204/0x3f0 [i915_bdw]
[ 13.157903] [<ffffffffa02e2c7f>] i915_driver_load+0x5cf/0xf90 [i915_bdw]
[ 13.157927] [<ffffffffa01a2ce2>] drm_dev_register+0xa2/0x1e0 [drm]
[ 13.157943] [<ffffffffa01a4be2>] drm_get_pci_dev+0x92/0x140 [drm]
[ 13.157966] [<ffffffffa02636eb>] i915_pci_probe+0x3b/0x60 [i915_bdw]
[ 13.157972] [<ffffffff813a61e5>] local_pci_probe+0x45/0xa0
[ 13.157976] [<ffffffff813a7485>] ? pci_match_device+0xc5/0xd0
[ 13.157981] [<ffffffff813a75a9>] pci_device_probe+0xd9/0x130
[ 13.157987] [<ffffffff8149355d>] driver_probe_device+0x12d/0x3e0
[ 13.157991] [<ffffffff814938e3>] __driver_attach+0x93/0xa0
[ 13.157995] [<ffffffff81493850>] ? __device_attach+0x40/0x40
[ 13.158000] [<ffffffff814914c3>] bus_for_each_dev+0x63/0xa0
[ 13.158004] [<ffffffff81492f0e>] driver_attach+0x1e/0x20
[ 13.158007] [<ffffffff81492af0>] bus_add_driver+0x180/0x250
[ 13.158013] [<ffffffffa032f000>] ? 0xffffffffa032efff
[ 13.158017] [<ffffffff81493f64>] driver_register+0x64/0xf0
[ 13.158021] [<ffffffffa032f000>] ? 0xffffffffa032efff
[ 13.158026] [<ffffffff813a5b7c>] __pci_register_driver+0x4c/0x50
[ 13.158039] [<ffffffffa01a4daa>] drm_pci_init+0x11a/0x130 [drm]
[ 13.158044] [<ffffffffa032f000>] ? 0xffffffffa032efff
[ 13.158066] [<ffffffffa032f06a>] i915_init+0x6a/0x6c [i915_bdw]
[ 13.158070] [<ffffffff8100214a>] do_one_initcall+0xfa/0x1b0
[ 13.158076] [<ffffffff810598d3>] ? set_memory_nx+0x43/0x50
[ 13.158082] [<ffffffff810e1f8d>] load_module+0x12dd/0x1b40
[ 13.158087] [<ffffffff810dda30>] ? store_uevent+0x40/0x40
[ 13.158093] [<ffffffff810e2966>] SyS_finit_module+0x86/0xb0
[ 13.158098] [<ffffffff8172c87f>] tracesys+0xe1/0xe6
[ 13.158101] ---[ end trace 5b57c64d53011e99 ]---

[Additional Information]
Base Image: somerville-trusty-amd64-iso-20140620-0.iso
Kernel Version: 3.13.0-32-generic
CPU: Genuine Intel(R) CPU 0000 @ 1.60GHz
GPU: Intel Corporation Broadwell-U Integrated Graphics [8086:1616] (rev 06)