[PATCH v8 3/4] drm/xe: Use device wedged event

[Raag Jadav]

This was previously attempted as xe specific reset uevent but dropped
in commit 77a0d4d1cea2 ("drm/xe/uapi: Remove reset uevent for now")
as part of refactoring.

Now that we have device wedged event provided by DRM core, make use
of it and support both driver rebind and bus-reset based recovery.
With this in place userspace will be notified of wedged device, on
the basis of which, userspace may take respective action to recover
the device.

$ udevadm monitor --property --kernel
monitor will print the received events for:
KERNEL - the kernel uevent

KERNEL[265.802982] change   /devices/pci0000:00/0000:00:01.0/0000:01:00.0/0000:02:01.0/0000:03:00.0/drm/card0 (drm)
ACTION=change
DEVPATH=/devices/pci0000:00/0000:00:01.0/0000:01:00.0/0000:02:01.0/0000:03:00.0/drm/card0
SUBSYSTEM=drm
WEDGED=rebind,bus-reset
DEVNAME=/dev/dri/card0
DEVTYPE=drm_minor
SEQNUM=5208
MAJOR=226
MINOR=0

v2: Change authorship to Himal (Aravind)
    Add uevent for all device wedged cases (Aravind)
v3: Generic re-implementation in DRM subsystem (Lucas)
v4: Change authorship to Raag (Aravind)

Signed-off-by: Raag Jadav <raag.jadav at intel.com>
---
 drivers/gpu/drm/xe/xe_device.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
index 2da4affe4dfd..2477cf043397 100644
--- a/drivers/gpu/drm/xe/xe_device.c
+++ b/drivers/gpu/drm/xe/xe_device.c
@@ -999,11 +999,12 @@ static void xe_device_wedged_fini(struct drm_device *drm, void *arg)
  * xe_device_declare_wedged - Declare device wedged
  * @xe: xe device instance
  *
- * This is a final state that can only be cleared with a mudule
+ * This is a final state that can only be cleared with a module
  * re-probe (unbind + bind).
  * In this state every IOCTL will be blocked so the GT cannot be used.
  * In general it will be called upon any critical error such as gt reset
- * failure or guc loading failure.
+ * failure or guc loading failure. Userspace will be notified of this state
+ * by a DRM uevent.
  * If xe.wedged module parameter is set to 2, this function will be called
  * on every single execution timeout (a.k.a. GPU hang) right after devcoredump
  * snapshot capture. In this mode, GT reset won't be attempted so the state of
@@ -1033,6 +1034,10 @@ void xe_device_declare_wedged(struct xe_device *xe)
 			"IOCTLs and executions are blocked. Only a rebind may clear the failure\n"
 			"Please file a _new_ bug report at https://gitlab.freedesktop.org/drm/xe/kernel/issues/new\n",
 			dev_name(xe->drm.dev));
+
+		/* Notify userspace of wedged device */
+		drm_dev_wedged_event(&xe->drm,
+				     DRM_WEDGE_RECOVERY_REBIND | DRM_WEDGE_RECOVERY_BUS_RESET);
 	}
 
 	for_each_gt(gt, xe, id)
-- 
2.34.1