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Imre Deak 6ab92afc95 drm/i915: Prevent the system suspend complete optimization
Since

commit bac2a909a0
Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Date:   Wed Jan 21 02:17:42 2015 +0100

    PCI / PM: Avoid resuming PCI devices during system suspend

PCI devices will default to allowing the system suspend complete
optimization where devices are not woken up during system suspend if
they were already runtime suspended. This however breaks the i915/HDA
drivers for two reasons:

- The i915 driver has system suspend specific steps that it needs to
  run, that bring the device to a different state than its runtime
  suspended state.

- The HDA driver's suspend handler requires power that it will request
  from the i915 driver's power domain handler. This in turn requires the
  i915 driver to runtime resume itself, but this won't be possible if the
  suspend complete optimization is in effect: in this case the i915
  runtime PM is disabled and trying to get an RPM reference returns
  -EACCESS.

Solve this by requiring the PCI/PM core to resume the device during
system suspend which in effect disables the suspend complete optimization.

Regardless of the above commit the optimization stayed disabled for DRM
devices until

commit d14d2a8453
Author: Lukas Wunner <lukas@wunner.de>
Date:   Wed Jun 8 12:49:29 2016 +0200

    drm: Remove dev_pm_ops from drm_class

so this patch is in practice a fix for this commit. Another reason for
the bug staying hidden for so long is that the optimization for a device
is disabled if it's disabled for any of its children devices. i915 may
have a backlight device as its child which doesn't support runtime PM
and so doesn't allow the optimization either.  So if this backlight
device got registered the bug stayed hidden.

Credits to Marta, Tomi and David who enabled pstore logging,
that caught one instance of this issue across a suspend/
resume-to-ram and Ville who rememberd that the optimization was enabled
for some devices at one point.

The first WARN triggered by the problem:

[ 6250.746445] WARNING: CPU: 2 PID: 17384 at drivers/gpu/drm/i915/intel_runtime_pm.c:2846 intel_runtime_pm_get+0x6b/0xd0 [i915]
[ 6250.746448] pm_runtime_get_sync() failed: -13
[ 6250.746451] Modules linked in: snd_hda_intel i915 vgem snd_hda_codec_hdmi x86_pkg_temp_thermal intel_powerclamp coretemp crct10dif_pclmul crc32_pclmul
snd_hda_codec_realtek snd_hda_codec_generic ghash_clmulni_intel e1000e snd_hda_codec snd_hwdep snd_hda_core ptp mei_me pps_core snd_pcm lpc_ich mei prime_
numbers i2c_hid i2c_designware_platform i2c_designware_core [last unloaded: i915]
[ 6250.746512] CPU: 2 PID: 17384 Comm: kworker/u8:0 Tainted: G     U  W       4.11.0-rc5-CI-CI_DRM_334+ #1
[ 6250.746515] Hardware name:                  /NUC5i5RYB, BIOS RYBDWi35.86A.0362.2017.0118.0940 01/18/2017
[ 6250.746521] Workqueue: events_unbound async_run_entry_fn
[ 6250.746525] Call Trace:
[ 6250.746530]  dump_stack+0x67/0x92
[ 6250.746536]  __warn+0xc6/0xe0
[ 6250.746542]  ? pci_restore_standard_config+0x40/0x40
[ 6250.746546]  warn_slowpath_fmt+0x46/0x50
[ 6250.746553]  ? __pm_runtime_resume+0x56/0x80
[ 6250.746584]  intel_runtime_pm_get+0x6b/0xd0 [i915]
[ 6250.746610]  intel_display_power_get+0x1b/0x40 [i915]
[ 6250.746646]  i915_audio_component_get_power+0x15/0x20 [i915]
[ 6250.746654]  snd_hdac_display_power+0xc8/0x110 [snd_hda_core]
[ 6250.746661]  azx_runtime_resume+0x218/0x280 [snd_hda_intel]
[ 6250.746667]  pci_pm_runtime_resume+0x76/0xa0
[ 6250.746672]  __rpm_callback+0xb4/0x1f0
[ 6250.746677]  ? pci_restore_standard_config+0x40/0x40
[ 6250.746682]  rpm_callback+0x1f/0x80
[ 6250.746686]  ? pci_restore_standard_config+0x40/0x40
[ 6250.746690]  rpm_resume+0x4ba/0x740
[ 6250.746698]  __pm_runtime_resume+0x49/0x80
[ 6250.746703]  pci_pm_suspend+0x57/0x140
[ 6250.746709]  dpm_run_callback+0x6f/0x330
[ 6250.746713]  ? pci_pm_freeze+0xe0/0xe0
[ 6250.746718]  __device_suspend+0xf9/0x370
[ 6250.746724]  ? dpm_watchdog_set+0x60/0x60
[ 6250.746730]  async_suspend+0x1a/0x90
[ 6250.746735]  async_run_entry_fn+0x34/0x160
[ 6250.746741]  process_one_work+0x1f2/0x6d0
[ 6250.746749]  worker_thread+0x49/0x4a0
[ 6250.746755]  kthread+0x107/0x140
[ 6250.746759]  ? process_one_work+0x6d0/0x6d0
[ 6250.746763]  ? kthread_create_on_node+0x40/0x40
[ 6250.746768]  ret_from_fork+0x2e/0x40
[ 6250.746778] ---[ end trace 102a62fd2160f5e6 ]---

v2:
- Use the new pci_dev->needs_resume flag, to avoid any overhead during
  the ->pm_prepare hook. (Rafael)

v3:
- Update commit message to reference the actual regressing commit.
  (Lukas)

v4:
- Rebase on v4 of patch 1/2.

Fixes: d14d2a8453 ("drm: Remove dev_pm_ops from drm_class")
References: https://bugs.freedesktop.org/show_bug.cgi?id=100378
References: https://bugs.freedesktop.org/show_bug.cgi?id=100770
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Marta Lofstedt <marta.lofstedt@intel.com>
Cc: David Weinehall <david.weinehall@linux.intel.com>
Cc: Tomi Sarvela <tomi.p.sarvela@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Lukas Wunner <lukas@wunner.de>
Cc: linux-pci@vger.kernel.org
Cc: <stable@vger.kernel.org> # v4.10.x: 4d071c3 - PCI/PM: Add needs_resume flag
Cc: <stable@vger.kernel.org> # v4.10.x
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reported-and-tested-by: Marta Lofstedt <marta.lofstedt@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1493726649-32094-2-git-send-email-imre.deak@intel.com
(cherry picked from commit adfdf85d79)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2017-06-07 16:31:13 +03:00
arch Merge branch 'akpm' (patches from Andrew) 2017-06-02 15:49:46 -07:00
block block: Avoid that blk_exit_rl() triggers a use-after-free 2017-06-01 13:07:55 -06:00
certs scripts/spelling.txt: add "intialise(d)" pattern and fix typo instances 2017-05-08 17:15:13 -07:00
crypto crypto: skcipher - Add missing API setkey checks 2017-05-18 13:04:05 +08:00
Documentation Pin control fixes for v4.12: 2017-05-29 10:05:19 -07:00
drivers drm/i915: Prevent the system suspend complete optimization 2017-06-07 16:31:13 +03:00
firmware firmware/Makefile: force recompilation if makefile changes 2017-05-08 17:15:10 -07:00
fs fs/ufs: Set UFS default maximum bytes per file 2017-06-04 16:33:54 -07:00
include Fixes for 4.12-rc 2017-06-04 10:41:32 -07:00
init Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-05-10 10:30:46 -07:00
ipc mm: introduce kv[mz]alloc helpers 2017-05-08 17:15:12 -07:00
kernel Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching 2017-06-02 08:59:17 -07:00
lib test_bpf: Add a couple of tests for BPF_JSGE. 2017-05-25 14:37:56 -04:00
mm mm: consider memblock reservations for deferred memory initialization sizing 2017-06-02 15:07:38 -07:00
net NFS client bugfixes for Linux 4.12 2017-06-04 11:56:53 -07:00
samples samples/bpf: run cleanup routines when receiving SIGTERM 2017-05-11 21:43:30 -04:00
scripts scripts/gdb: make lx-dmesg command work (reliably) 2017-06-02 15:07:38 -07:00
security Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-05-09 09:12:53 -07:00
sound sound fixes for 4.12-rc4 2017-06-02 09:40:47 -07:00
tools powerpc fixes for 4.12 #4 2017-05-27 09:28:34 -07:00
usr initramfs: fix disabling of initramfs (and its compression) 2017-06-02 15:07:37 -07:00
virt KVM: arm/arm64: Hold slots_lock when unregistering kvm io bus devices 2017-05-18 11:18:16 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap power supply and reset changes for the v4.12 series (part 2) 2017-05-12 12:02:21 -07:00
COPYING
CREDITS avr32: remove support for AVR32 architecture 2017-05-01 09:27:15 +02:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig
MAINTAINERS RTC for 4.12 #2 2017-06-04 11:29:32 -07:00
Makefile Linux 4.12-rc4 2017-06-04 16:47:43 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.