drm: Flush output polling on shutdown

We need to mark the output polling as disabled to prevent concurrent
irqs from queuing new work as shutdown the probe -- causing that work to
execute after we have freed the structs:

<4> [341.846490] DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock))
<4> [341.846497] WARNING: CPU: 3 PID: 3300 at kernel/locking/mutex-debug.c:103 mutex_destroy+0x49/0x50
<4> [341.846508] Modules linked in: i915(-) vgem thunderbolt snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic mei_hdcp x86_pkg_temp_thermal coretemp crct10dif_pclmul crc32_pclmul ghash_clmulni_intel snd_hda_codec snd_hwdep snd_hda_core snd_pcm mcs7830 btusb usbnet btrtl mii btbcm btintel bluetooth ecdh_generic ecc mei_me mei prime_numbers i2c_hid pinctrl_sunrisepoint pinctrl_intel [last unloaded: i915]
<4> [341.846546] CPU: 3 PID: 3300 Comm: i915_module_loa Tainted: G     U            5.2.0-rc2-CI-CI_DRM_6175+ #1
<4> [341.846553] Hardware name: Dell Inc. XPS 13 9360/0823VW, BIOS 2.9.0 07/09/2018
<4> [341.846560] RIP: 0010:mutex_destroy+0x49/0x50
<4> [341.846565] Code: 00 00 5b c3 e8 a8 9f 3b 00 85 c0 74 ed 8b 05 3e 55 23 01 85 c0 75 e3 48 c7 c6 00 d0 08 82 48 c7 c7 a8 aa 07 82 e8 e7 08 fa ff <0f> 0b eb cc 0f 1f 00 48 b8 11 11 11 11 11 11 11 11 48 89 76 20 48
<4> [341.846578] RSP: 0018:ffffc900006cfdb0 EFLAGS: 00010286
<4> [341.846583] RAX: 0000000000000000 RBX: ffff88826759a168 RCX: 0000000000000000
<4> [341.846589] RDX: 0000000000000002 RSI: 0000000000000000 RDI: ffffffff8112844c
<4> [341.846595] RBP: ffff8882708fa548 R08: 0000000000000000 R09: 0000000000039600
<4> [341.846601] R10: 0000000000000000 R11: 0000000000000ce4 R12: ffffffffa07de1e0
<4> [341.846607] R13: 0000000000000000 R14: 0000000000000000 R15: ffffffffa07de2d0
<4> [341.846613] FS:  00007f62b5ae0e40(0000) GS:ffff888276380000(0000) knlGS:0000000000000000
<4> [341.846620] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4> [341.846626] CR2: 000055a4e064f4a0 CR3: 0000000266b16006 CR4: 00000000003606e0
<4> [341.846632] Call Trace:
<4> [341.846639]  drm_fb_helper_fini.part.17+0xb3/0x100
<4> [341.846682]  intel_fbdev_fini+0x20/0x80 [i915]
<4> [341.846722]  intel_modeset_cleanup+0x9a/0x140 [i915]
<4> [341.846750]  i915_driver_unload+0xa3/0x100 [i915]
<4> [341.846778]  i915_pci_remove+0x19/0x30 [i915]
<4> [341.846784]  pci_device_remove+0x36/0xb0
<4> [341.846790]  device_release_driver_internal+0xd3/0x1b0
<4> [341.846795]  driver_detach+0x3f/0x80
<4> [341.846800]  bus_remove_driver+0x53/0xd0
<4> [341.846805]  pci_unregister_driver+0x25/0xa0
<4> [341.846843]  i915_exit+0x16/0x1c [i915]
<4> [341.846849]  __se_sys_delete_module+0x162/0x210
<4> [341.846855]  ? trace_hardirqs_off_thunk+0x1a/0x1c
<4> [341.846859]  ? do_syscall_64+0xd/0x1c0
<4> [341.846864]  do_syscall_64+0x55/0x1c0
<4> [341.846869]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
<4> [341.846875] RIP: 0033:0x7f62b51871b7
<4> [341.846881] Code: 73 01 c3 48 8b 0d d1 8c 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 b0 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 8c 2c 00 f7 d8 64 89 01 48
<4> [341.846897] RSP: 002b:00007ffe7a227138 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0
<4> [341.846904] RAX: ffffffffffffffda RBX: 00007ffe7a2272b0 RCX: 00007f62b51871b7
<4> [341.846910] RDX: 0000000000000001 RSI: 0000000000000800 RDI: 0000557cd6b55948
<4> [341.846916] RBP: 0000557cd6b558e0 R08: 0000557cd6b5594c R09: 00007ffe7a227160
<4> [341.846922] R10: 00007ffe7a226134 R11: 0000000000000206 R12: 0000000000000000
<4> [341.846927] R13: 00007ffe7a227820 R14: 0000000000000000 R15: 0000000000000000
<4> [341.846936] irq event stamp: 3547847
<4> [341.846940] hardirqs last  enabled at (3547847): [<ffffffff819aad2c>] _raw_spin_unlock_irqrestore+0x4c/0x60
<4> [341.846949] hardirqs last disabled at (3547846): [<ffffffff819aab9d>] _raw_spin_lock_irqsave+0xd/0x50
<4> [341.846957] softirqs last  enabled at (3547376): [<ffffffff81c0033a>] __do_softirq+0x33a/0x4b9
<4> [341.846966] softirqs last disabled at (3547367): [<ffffffff810b6379>] irq_exit+0xa9/0xc0
<4> [341.846973] WARNING: CPU: 3 PID: 3300 at kernel/locking/mutex-debug.c:103 mutex_destroy+0x49/0x50
<4> [341.846980] ---[ end trace ba94ca8952ba970e ]---
<7> [341.866547] [drm:intel_dp_detect [i915]] MST support? port A: no, sink: no, modparam: yes
<7> [341.890480] [drm:drm_add_display_info] non_desktop set to 0
<7> [341.890530] [drm:drm_add_edid_modes] ELD: no CEA Extension found
<7> [341.890537] [drm:drm_add_display_info] non_desktop set to 0
<7> [341.890578] [drm:drm_helper_probe_single_connector_modes] [CONNECTOR:86:eDP-1] probed modes :
<7> [341.890589] [drm:drm_mode_debug_printmodeline] Modeline "3200x1800": 60 373250 3200 3248 3280 3360 1800 1803 1808 1852 0x48 0xa
<7> [341.890602] [drm:drm_mode_debug_printmodeline] Modeline "3200x1800": 48 298600 3200 3248 3280 3360 1800 1803 1808 1852 0x40 0xa
<4> [341.890628] general protection fault: 0000 [#1] PREEMPT SMP PTI
<4> [341.890636] CPU: 0 PID: 508 Comm: kworker/0:4 Tainted: G     U  W         5.2.0-rc2-CI-CI_DRM_6175+ #1
<4> [341.890646] Hardware name: Dell Inc. XPS 13 9360/0823VW, BIOS 2.9.0 07/09/2018
<4> [341.890655] Workqueue: events output_poll_execute
<4> [341.890663] RIP: 0010:drm_setup_crtcs+0x13e/0xbe0
<4> [341.890669] Code: 00 41 8b 44 24 58 85 c0 0f 8e f9 01 00 00 44 8b 6c 24 20 44 8b 74 24 28 31 db 31 ed 49 8b 44 24 60 48 63 d5 44 89 ee 83 c5 01 <48> 8b 04 d0 44 89 f2 48 8b 38 48 8b 87 88 01 00 00 48 8b 40 20 e8
<4> [341.890686] RSP: 0018:ffffc9000033fd40 EFLAGS: 00010202
<4> [341.890692] RAX: 6b6b6b6b6b6b6b6b RBX: 0000000000000002 RCX: 0000000000000000
<4> [341.890700] RDX: 0000000000000001 RSI: 0000000000000c80 RDI: 00000000ffffffff
<4> [341.890707] RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
<4> [341.890715] R10: 0000000000000c80 R11: 0000000000000000 R12: ffff888267599fe8
<4> [341.890722] R13: 0000000000000c80 R14: 0000000000000708 R15: 0000000000000007
<4> [341.890730] FS:  0000000000000000(0000) GS:ffff888276200000(0000) knlGS:0000000000000000
<4> [341.890739] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4> [341.890745] CR2: 000055a4e064f4a0 CR3: 000000026d234003 CR4: 00000000003606f0
<4> [341.890752] Call Trace:
<4> [341.890760]  drm_fb_helper_hotplug_event.part.24+0x89/0xb0
<4> [341.890768]  drm_kms_helper_hotplug_event+0x21/0x30
<4> [341.890774]  output_poll_execute+0x9d/0x1a0
<4> [341.890782]  process_one_work+0x245/0x610
<4> [341.890790]  worker_thread+0x37/0x380
<4> [341.890796]  ? process_one_work+0x610/0x610
<4> [341.890802]  kthread+0x119/0x130
<4> [341.890808]  ? kthread_park+0x80/0x80
<4> [341.890815]  ret_from_fork+0x3a/0x50

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109964Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190603135910.15979-2-chris@chris-wilson.co.uk

drivers/gpu/drm/drm_probe_helper.c

@@ -575,6 +575,9 @@ static void output_poll_execute(struct work_struct *work)
 	enum drm_connector_status old_status;
 	bool repoll = false, changed;
 
+	if (!dev->mode_config.poll_enabled)
+		return;
+
 	/* Pick up any changes detected by the probe functions. */
 	changed = dev->mode_config.delayed_event;
 	dev->mode_config.delayed_event = false;
@@ -729,7 +732,11 @@ EXPORT_SYMBOL(drm_kms_helper_poll_init);
  */
 void drm_kms_helper_poll_fini(struct drm_device *dev)
 {
-	drm_kms_helper_poll_disable(dev);
+	if (!dev->mode_config.poll_enabled)
+		return;
+
+	dev->mode_config.poll_enabled = false;
+	cancel_delayed_work_sync(&dev->mode_config.output_poll_work);
 }
 EXPORT_SYMBOL(drm_kms_helper_poll_fini);