From 42bf7b46a5de03c8e2dd28a1f105bc28b6485243 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Bj=C3=B8rn=20Mork?= Date: Wed, 30 Mar 2016 11:08:33 +0200 Subject: [PATCH] drm/i915: fix deadlock on lid open MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit e2c8b8701e2d moved modeset locking inside resume/suspend functions, but missed a code path only executed on lid close/open on older hardware. The result was a deadlock when closing and opening the lid without suspending on such hardware: ============================================= [ INFO: possible recursive locking detected ] 4.6.0-rc1 #385 Not tainted --------------------------------------------- kworker/0:3/88 is trying to acquire lock: (&dev->mode_config.mutex){+.+.+.}, at: [] intel_display_resume+0x4a/0x12f [i915] but task is already holding lock: (&dev->mode_config.mutex){+.+.+.}, at: [] drm_modeset_lock_all+0x3e/0xa6 [drm] other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&dev->mode_config.mutex); lock(&dev->mode_config.mutex); *** DEADLOCK *** May be due to missing lock nesting notation 7 locks held by kworker/0:3/88: #0: ("kacpi_notify"){++++.+}, at: [] process_one_work+0x14a/0x50b #1: ((&dpc->work)#2){+.+.+.}, at: [] process_one_work+0x14a/0x50b #2: ((acpi_lid_notifier).rwsem){++++.+}, at: [] __blocking_notifier_call_chain+0x34/0x65 #3: (&dev_priv->modeset_restore_lock){+.+.+.}, at: [] intel_lid_notify+0x3c/0xd9 [i915] #4: (&dev->mode_config.mutex){+.+.+.}, at: [] drm_modeset_lock_all+0x3e/0xa6 [drm] #5: (crtc_ww_class_acquire){+.+.+.}, at: [] drm_modeset_lock_all+0x48/0xa6 [drm] #6: (crtc_ww_class_mutex){+.+.+.}, at: [] modeset_lock+0x13c/0x1cd [drm] stack backtrace: CPU: 0 PID: 88 Comm: kworker/0:3 Not tainted 4.6.0-rc1 #385 Hardware name: LENOVO 2776LEG/2776LEG, BIOS 6EET55WW (3.15 ) 12/19/2011 Workqueue: kacpi_notify acpi_os_execute_deferred 0000000000000000 ffff88022fd5f990 ffffffff8124af06 ffffffff825b39c0 ffffffff825b39c0 ffff88022fd5fa60 ffffffff8108f547 ffff88022fd5fa70 000000008108e817 ffff880230236cc0 0000000000000000 ffffffff825b39c0 Call Trace: [] dump_stack+0x67/0x90 [] __lock_acquire+0xdb5/0xf71 [] ? look_up_lock_class+0xbe/0x10a [] lock_acquire+0x137/0x1cb [] ? lock_acquire+0x137/0x1cb [] ? intel_display_resume+0x4a/0x12f [i915] [] mutex_lock_nested+0x7e/0x3a4 [] ? intel_display_resume+0x4a/0x12f [i915] [] ? intel_display_resume+0x4a/0x12f [i915] [] ? modeset_lock+0x13c/0x1cd [drm] [] intel_display_resume+0x4a/0x12f [i915] [] ? intel_display_resume+0x4a/0x12f [i915] [] ? modeset_lock+0x13c/0x1cd [drm] [] ? modeset_lock+0x13c/0x1cd [drm] [] ? drm_modeset_lock+0x17/0x24 [drm] [] ? drm_modeset_lock_all_ctx+0x87/0xa1 [drm] [] intel_lid_notify+0xb0/0xd9 [i915] [] notifier_call_chain+0x4a/0x6c [] __blocking_notifier_call_chain+0x4d/0x65 [] blocking_notifier_call_chain+0x14/0x16 [] acpi_lid_send_state+0x83/0xad [button] [] acpi_button_notify+0x41/0x132 [button] [] acpi_device_notify+0x19/0x1b [] acpi_ev_notify_dispatch+0x49/0x64 [] acpi_os_execute_deferred+0x14/0x20 [] process_one_work+0x265/0x50b [] worker_thread+0x1fc/0x2dd [] ? rescuer_thread+0x309/0x309 [] ? rescuer_thread+0x309/0x309 [] kthread+0xe0/0xe8 [] ? local_clock+0x19/0x22 [] ret_from_fork+0x22/0x40 [] ? kthread_create_on_node+0x1b5/0x1b5 Fixes: e2c8b8701e2d ("drm/i915: Use atomic helpers for suspend, v2.") Cc: Maarten Lankhorst Signed-off-by: Bjørn Mork Signed-off-by: Maarten Lankhorst Link: http://patchwork.freedesktop.org/patch/msgid/1459328913-13719-1-git-send-email-bjorn@mork.no (cherry picked from commit 9f54d4bd5808b5c892a44c539c126b71d299f341) Signed-off-by: Jani Nikula --- drivers/gpu/drm/i915/intel_lvds.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c index 30a8403a8f4f..cd9fe609aefb 100644 --- a/drivers/gpu/drm/i915/intel_lvds.c +++ b/drivers/gpu/drm/i915/intel_lvds.c @@ -478,11 +478,8 @@ static int intel_lid_notify(struct notifier_block *nb, unsigned long val, * and as part of the cleanup in the hw state restore we also redisable * the vga plane. */ - if (!HAS_PCH_SPLIT(dev)) { - drm_modeset_lock_all(dev); + if (!HAS_PCH_SPLIT(dev)) intel_display_resume(dev); - drm_modeset_unlock_all(dev); - } dev_priv->modeset_restore = MODESET_DONE; -- 2.30.2