drm/i915: Prevent the system suspend complete optimization
Since commit bac2a909 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 d14d2a84 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: d14d2a84 ("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: 4d071c32 - 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
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