drm/i915/lvds: Move acpi lid notification registration to registration phase

Delay registering ourselves with the acpi lid notification mechanism
until we are registering the connectors after initialisation is
complete. This prevents a possibility of trying to handle the lid
notification before we are ready with the danger of chasing
uninitialised function pointers.

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
 IP:           (null)
 PGD 0 P4D 0
 Oops: 0010 [#1] PREEMPT SMP PTI
 Modules linked in: arc4(+) iwldvm(+) i915(+) mac80211 i2c_algo_bit coretemp mei_wdt iwlwifi drm_kms_helper kvm_intel wmi_bmof iTCO_wdt iTCO_vendor_support kvm snd_hda_codec_conexant snd_hda_codec_generic drm psmouse cfg80211 irqbypass input_leds pcspkr i2c_i801 snd_hda_intel snd_hda_codec thinkpad_acpi snd_hda_core mei_me lpc_ich snd_hwdep e1000e wmi nvram snd_pcm mei snd_timer shpchp ptp pps_core rfkill syscopyarea snd intel_agp sysfillrect intel_gtt soundcore sysimgblt battery led_class fb_sys_fops ac rtc_cmos agpgart evdev mac_hid acpi_cpufreq ip_tables x_tables ext4 crc32c_generic crc16 mbcache jbd2 fscrypto crypto_simd glue_helper cryptd aes_x86_64 xts algif_skcipher af_alg dm_crypt dm_mod sd_mod uas usb_storage serio_raw atkbd libps2 ahci libahci uhci_hcd libata scsi_mod ehci_pci
  ehci_hcd usbcore usb_common i8042 serio
 CPU: 1 PID: 378 Comm: systemd-logind Not tainted 4.16.8-1-ARCH #1
 Hardware name: LENOVO 7454CTO/7454CTO, BIOS 6DET72WW (3.22 ) 10/25/2012
 RIP: 0010:          (null)
 RSP: 0018:ffffaf4580c33a18 EFLAGS: 00010287
 RAX: 0000000000000000 RBX: ffff947533558000 RCX: 000000000000003e
 RDX: ffffffffc0aa80c0 RSI: ffffaf4580c33a3c RDI: ffff947534e4c000
 RBP: ffff947533558338 R08: ffff947534598930 R09: ffffffffc0a928b1
 R10: ffffd8f181d5fd40 R11: 0000000000000000 R12: ffffffffc0a928b1
 R13: ffff947533558368 R14: ffffffffc0a928a9 R15: ffff947534e4c000
 FS:  00007f3dc4ddb940(0000) GS:ffff947539280000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000000 CR3: 000000006e214000 CR4: 00000000000406e0
 Call Trace:
  ?  intel_modeset_setup_hw_state+0x385/0xf60 [i915]
  ? __intel_display_resume+0x1e/0xc0 [i915]
  ? intel_display_resume+0xcc/0x120 [i915]
  ? intel_lid_notify+0xbc/0xc0 [i915]
  ? notifier_call_chain+0x47/0x70
  ? blocking_notifier_call_chain+0x3e/0x60
  ? acpi_lid_notify_state+0x8f/0x1d0
  ? acpi_lid_update_state+0x49/0x70
  ? acpi_lid_input_open+0x60/0x90
  ? input_open_device+0x5d/0xa0
  ? evdev_open+0x1ba/0x1e0 [evdev]
  ? chrdev_open+0xa3/0x1b0
  ? cdev_put.part.0+0x20/0x20
  ? do_dentry_open+0x14c/0x300
  ? path_openat+0x30c/0x1240
  ? current_time+0x16/0x60
  ? do_filp_open+0x93/0x100
  ? __check_object_size+0xfb/0x180
  ? do_sys_open+0x186/0x210
  ? do_syscall_64+0x74/0x190
  ?  entry_SYSCALL_64_after_hwframe+0x3d/0xa2
 Code:  Bad RIP value.
 RIP:           (null) RSP: ffffaf4580c33a18
 CR2: 0000000000000000

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=106559
Fixes: c1c7af6089 ("drm/i915: force mode set at lid open time")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180518074840.16194-1-chris@chris-wilson.co.uk
Cc: stable@vger.kernel.org
(cherry picked from commit e578a570dc)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

drivers/gpu/drm/i915/intel_lvds.c

@@ -574,6 +574,36 @@ static int intel_lid_notify(struct notifier_block *nb, unsigned long val,
 	return NOTIFY_OK;
 }
 
+static int
+intel_lvds_connector_register(struct drm_connector *connector)
+{
+	struct intel_lvds_connector *lvds = to_lvds_connector(connector);
+	int ret;
+
+	ret = intel_connector_register(connector);
+	if (ret)
+		return ret;
+
+	lvds->lid_notifier.notifier_call = intel_lid_notify;
+	if (acpi_lid_notifier_register(&lvds->lid_notifier)) {
+		DRM_DEBUG_KMS("lid notifier registration failed\n");
+		lvds->lid_notifier.notifier_call = NULL;
+	}
+
+	return 0;
+}
+
+static void
+intel_lvds_connector_unregister(struct drm_connector *connector)
+{
+	struct intel_lvds_connector *lvds = to_lvds_connector(connector);
+
+	if (lvds->lid_notifier.notifier_call)
+		acpi_lid_notifier_unregister(&lvds->lid_notifier);
+
+	intel_connector_unregister(connector);
+}
+
 /**
  * intel_lvds_destroy - unregister and free LVDS structures
  * @connector: connector to free
@@ -586,9 +616,6 @@ static void intel_lvds_destroy(struct drm_connector *connector)
 	struct intel_lvds_connector *lvds_connector =
 		to_lvds_connector(connector);
 
-	if (lvds_connector->lid_notifier.notifier_call)
-		acpi_lid_notifier_unregister(&lvds_connector->lid_notifier);
-
 	if (!IS_ERR_OR_NULL(lvds_connector->base.edid))
 		kfree(lvds_connector->base.edid);
 
@@ -609,8 +636,8 @@ static const struct drm_connector_funcs intel_lvds_connector_funcs = {
 	.fill_modes = drm_helper_probe_single_connector_modes,
 	.atomic_get_property = intel_digital_connector_atomic_get_property,
 	.atomic_set_property = intel_digital_connector_atomic_set_property,
-	.late_register = intel_connector_register,
+	.late_register = intel_lvds_connector_register,
-	.early_unregister = intel_connector_unregister,
+	.early_unregister = intel_lvds_connector_unregister,
 	.destroy = intel_lvds_destroy,
 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
 	.atomic_duplicate_state = intel_digital_connector_duplicate_state,
@@ -1158,12 +1185,6 @@ void intel_lvds_init(struct drm_i915_private *dev_priv)
 
 	lvds_encoder->a3_power = lvds & LVDS_A3_POWER_MASK;
 
-	lvds_connector->lid_notifier.notifier_call = intel_lid_notify;
-	if (acpi_lid_notifier_register(&lvds_connector->lid_notifier)) {
-		DRM_DEBUG_KMS("lid notifier registration failed\n");
-		lvds_connector->lid_notifier.notifier_call = NULL;
-	}
-
 	return;
 
 failed: