On 1/11/2022 12:26 PM, Christian König wrote:
Am 11.01.22 um 08:12 schrieb Somalapuram Amaranath:
AMDGPURESET uevent added to notify userspace,
collect dump_stack and amdgpu_reset_reg_dumps
Signed-off-by: Somalapuram Amaranath <Amaranath.Somalapuram@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/nv.c | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/nv.c
b/drivers/gpu/drm/amd/amdgpu/nv.c
index 2ec1ffb36b1f..41a2c37e825f 100644
--- a/drivers/gpu/drm/amd/amdgpu/nv.c
+++ b/drivers/gpu/drm/amd/amdgpu/nv.c
@@ -529,10 +529,41 @@ nv_asic_reset_method(struct amdgpu_device *adev)
}
}
+/**
+ * drm_sysfs_reset_event - generate a DRM uevent
+ * @dev: DRM device
+ *
+ * Send a uevent for the DRM device specified by @dev. Currently we
only
+ * set AMDGPURESET=1 in the uevent environment, but this could be
expanded to
+ * deal with other types of events.
+ *
+ * Any new uapi should be using the drm_sysfs_connector_status_event()
+ * for uevents on connector status change.
+ */
+void drm_sysfs_reset_event(struct drm_device *dev)
+{
+ char *event_string = "AMDGPURESET=1";
+ char *envp[2] = { event_string, NULL };
+
+ kobject_uevent_env(&dev->primary->kdev->kobj, KOBJ_CHANGE, envp);
That won't work like this.
kobject_uevent_env() needs to allocate memory to send the event to
userspace and that is not allowed while we do an reset. The Intel guys
felt into the same trap already.
What we could maybe do is to teach kobject_uevent_env() gfp flags and
make all allocations from the atomic pool.
Regards,
Christian.
Hi Amar,
I see another problem here,
We are sending the event at the GPU reset, but we are collecting the
register values only when the corresponding userspace agent calls a
read() on the respective sysfs entry.
There is a very fair possibility that the register values are reset by
the HW by then, and we are reading re-programmed values. At least there
will be a race().
I think we should change this design in such a way:
1. Get into gpu_reset()
2. collect the register values and save this context into a separate
file/node. Probably sending a trace_event here would be easiest way.
3. Send the drm event to the userspace client
4. The client reads from the trace file, and gets the data.
- Shashank
+}
+
+void amdgpu_reset_dumps(struct amdgpu_device *adev)
+{
+ struct drm_device *ddev = adev_to_drm(adev);
+ /* original raven doesn't have full asic reset */
+ if ((adev->apu_flags & AMD_APU_IS_RAVEN) &&
+ !(adev->apu_flags & AMD_APU_IS_RAVEN2))
+ return;
+ drm_sysfs_reset_event(ddev);
+ dump_stack();
+}
+
static int nv_asic_reset(struct amdgpu_device *adev)
{
int ret = 0;
+ amdgpu_reset_dumps(adev);
switch (nv_asic_reset_method(adev)) {
case AMD_RESET_METHOD_PCI:
dev_info(adev->dev, "PCI reset\n");
