[PATCH 4.9 061/108] drm/nouveau: Handle fbcon suspend/resume in seperate worker

Greg Kroah-Hartman
2017-06-15T18:00:24Z

From: Lyude Paul <lyude@redhat.com>

[ Upstream commit 15266ae38fe09dae07bd8812cb7a7717b1e1d992 ]

Resuming from RPM can happen while already holding
dev->mode_config.mutex. This means we can't actually handle fbcon in
any RPM resume workers, since restoring fbcon requires grabbing
dev->mode_config.mutex again. So move the fbcon suspend/resume code into
it's own worker, and rely on that instead to avoid deadlocking.

This fixes more deadlocks for runtime suspending the GPU on the ThinkPad
W541. Reproduction recipe:

- Get a machine with both optimus and a nvidia card with connectors
attached to it
- Wait for the nvidia GPU to suspend
- Attempt to manually reprobe any of the connectors on the nvidia GPU
using sysfs
- *deadlock*

[airlied: use READ_ONCE to address Hans's comment]

Signed-off-by: Lyude <lyude@redhat.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Kilian Singer <kilian.singer@quantumtechnology.info>
Cc: Lukas Wunner <lukas@wunner.de>
Cc: David Airlie <airlied@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/nouveau/nouveau_drv.h | 2 +
drivers/gpu/drm/nouveau/nouveau_fbcon.c | 43 +++++++++++++++++++++++++-------
2 files changed, 36 insertions(+), 9 deletions(-)

--- a/drivers/gpu/drm/nouveau/nouveau_drv.h
+++ b/drivers/gpu/drm/nouveau/nouveau_drv.h
@@ -164,6 +164,8 @@ struct nouveau_drm {
struct nouveau_display *display;
struct backlight_device *backlight;
struct work_struct hpd_work;
+ struct work_struct fbcon_work;
+ int fbcon_new_state;
#ifdef CONFIG_ACPI
struct notifier_block acpi_nb;
#endif
--- a/drivers/gpu/drm/nouveau/nouveau_fbcon.c
+++ b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
@@ -491,19 +491,43 @@ static const struct drm_fb_helper_funcs
.fb_probe = nouveau_fbcon_create,
};

+static void
+nouveau_fbcon_set_suspend_work(struct work_struct *work)
+{
+ struct nouveau_drm *drm = container_of(work, typeof(*drm), fbcon_work);
+ int state = READ_ONCE(drm->fbcon_new_state);
+
+ if (state == FBINFO_STATE_RUNNING)
+ pm_runtime_get_sync(drm->dev->dev);
+
+ console_lock();
+ if (state == FBINFO_STATE_RUNNING)
+ nouveau_fbcon_accel_restore(drm->dev);
+ drm_fb_helper_set_suspend(&drm->fbcon->helper, state);
+ if (state != FBINFO_STATE_RUNNING)
+ nouveau_fbcon_accel_save_disable(drm->dev);
+ console_unlock();
+
+ if (state == FBINFO_STATE_RUNNING) {
+ pm_runtime_mark_last_busy(drm->dev->dev);
+ pm_runtime_put_sync(drm->dev->dev);
+ }
+}
+
void
nouveau_fbcon_set_suspend(struct drm_device *dev, int state)
{
struct nouveau_drm *drm = nouveau_drm(dev);
- if (drm->fbcon) {
- console_lock();
- if (state == FBINFO_STATE_RUNNING)
- nouveau_fbcon_accel_restore(dev);
- drm_fb_helper_set_suspend(&drm->fbcon->helper, state);
- if (state != FBINFO_STATE_RUNNING)
- nouveau_fbcon_accel_save_disable(dev);
- console_unlock();
- }
+
+ if (!drm->fbcon)
+ return;
+
+ drm->fbcon_new_state = state;
+ /* Since runtime resume can happen as a result of a sysfs operation,
+ * it's possible we already have the console locked. So handle fbcon
+ * init/deinit from a seperate work thread
+ */
+ schedule_work(&drm->fbcon_work);
}

int
@@ -524,6 +548,7 @@ nouveau_fbcon_init(struct drm_device *de

fbcon->dev = dev;
drm->fbcon = fbcon;
+ INIT_WORK(&drm->fbcon_work, nouveau_fbcon_set_suspend_work);

drm_fb_helper_prepare(dev, &fbcon->helper, &nouveau_fbcon_helper_funcs);