drm/i915: WARN_ON(dev_priv->mm.busy)

[Jeremiah Mahler]

all,

On all my machines with Intel graphics I get the following warning
in the logs when the machine is suspended.  Apparently some part of
the graphics system is busy when it should be idle. This is present
on the latest linux-next 20150604.

  ...
  [   33.141747] Suspending console(s) (use no_console_suspend to debug)
  [   33.142146] wlan0: deauthenticating from 00:1a:70:5a:6e:0b by local
  choice (Reason: 3=DEAUTH_LEAVING)
  [   33.147395] queueing ieee80211 work while going to suspend
  [   33.151597] cfg80211: Calling CRDA to update world regulatory domain
  [   33.190430] sd 0:0:0:0: [sda] Synchronizing SCSI cache
  [   33.190523] sd 0:0:0:0: [sda] Stopping disk
  [   33.275743] ------------[ cut here ]------------
  [   33.275764] WARNING: CPU: 0 PID: 1617 at
  drivers/gpu/drm/i915/i915_gem.c:4808 i915_gem_suspend+0xe4/0xf0 [i915]()
  [   33.275766] WARN_ON(dev_priv->mm.busy)
  [   33.275811] Modules linked in: binfmt_misc snd_hda_codec_hdmi
  hid_generic isl29018(C) industrialio regmap_i2c cyapatp crc_itu_t usbhid
  hid arc4 x86_pkg_temp_thermal intel_powerclamp intel_rapl iosf_mbi
  coretemp ath9k tpm_infineon kvm_intel kvm ath9k_common ath9k_hw
  crct10dif_pclmul crc32_pclmul crc32c_intel chromeos_laptop ath mac80211
  ghash_clmulni_intel cryptd i915 cfg80211 pcspkr serio_raw sg ath3k btusb
  btrtl lpc_ich snd_hda_codec_realtek shpchp i2c_i801 mfd_core
  snd_hda_codec_generic btbcm btintel bluetooth snd_hda_intel battery
  snd_hda_codec ac i2c_algo_bit drm_kms_helper tpm_tis snd_hwdep tpm
  snd_hda_core drm snd_pcm video rfkill processor button snd_timer snd
  soundcore i2c_designware_pci i2c_designware_core evdev uvcvideo
  videobuf2_vmalloc videobuf2_memops videobuf2_core v4l2_common videodev
  [   33.275825]  media i2c_core fuse autofs4 ext4 crc16 mbcache jbd2
  sd_mod fan xhci_pci sdhci_acpi sdhci xhci_hcd mmc_core thermal
  thermal_sys usbcore ahci libahci usb_common libata scsi_mod
  [   33.275828] CPU: 0 PID: 1617 Comm: kworker/u4:4 Tainted: G         C
  4.1.0-rc6-next-20150604+ #207
  [   33.275829] Hardware name: Acer Peppy, BIOS          04/30/2014
  [   33.275834] Workqueue: events_unbound async_run_entry_fn
  [   33.275838]  0000000000000000 ffffffffa05b7908 ffffffff8152ca4d
  ffff880035effc58
  [   33.275840]  ffffffff8106bce1 ffff880073587f20 0000000000000000
  ffff880073580000
  [   33.275842]  ffff88003534f860 ffff880073580000 ffffffff8106bd5a
  ffffffffa05c74c1
  [   33.275843] Call Trace:
  [   33.275849]  [<ffffffff8152ca4d>] ? dump_stack+0x40/0x50
  [   33.275853]  [<ffffffff8106bce1>] ? warn_slowpath_common+0x81/0xb0
  [   33.275855]  [<ffffffff8106bd5a>] ? warn_slowpath_fmt+0x4a/0x50
  [   33.275865]  [<ffffffffa0520264>] ? i915_gem_suspend+0xe4/0xf0 [i915]
  [   33.275872]  [<ffffffffa04f48c1>] ? i915_drm_suspend+0x61/0x1b0
  [i915]
  [   33.275876]  [<ffffffff81302381>] ? pci_pm_suspend+0x71/0x140
  [   33.275878]  [<ffffffff81302310>] ? pci_pm_freeze+0xd0/0xd0
  [   33.275881]  [<ffffffff813e1699>] ? dpm_run_callback+0x39/0xd0
  [   33.275883]  [<ffffffff813e20d4>] ? __device_suspend+0xe4/0x300
  [   33.275884]  [<ffffffff813e230e>] ? async_suspend+0x1e/0x90
  [   33.275887]  [<ffffffff8108a893>] ? async_run_entry_fn+0x43/0x150
  [   33.275890]  [<ffffffff810828f8>] ? process_one_work+0x148/0x3b0
  [   33.275892]  [<ffffffff81082e8a>] ? worker_thread+0x4a/0x440
  [   33.275895]  [<ffffffff81082e40>] ? rescuer_thread+0x2e0/0x2e0
  [   33.275898]  [<ffffffff81088121>] ? kthread+0xc1/0xe0
  [   33.275901]  [<ffffffff81088060>] ?
  kthread_create_on_node+0x190/0x190
  [   33.275904]  [<ffffffff8153365f>] ? ret_from_fork+0x3f/0x70
  [   33.275907]  [<ffffffff81088060>] ?
  kthread_create_on_node+0x190/0x190
  [   33.275908] ---[ end trace e1c3eb5e163b3520 ]---
  [   33.560558] PM: suspend of devices complete after 423.034 msecs
  [   33.577985] PM: late suspend of devices complete after 17.589 msecs
  [   33.579036] xhci_hcd 0000:00:14.0: System wakeup enabled by ACPI
  [   33.594059] PM: noirq suspend of devices complete after 16.226 msecs
  [   33.594498] ACPI: Preparing to enter system sleep state S3
  [   33.595066] ACPI : EC: EC stopped
  ...

-- 
- Jeremiah Mahler