On 1/17/2022 3:49 PM, Christian König
wrote:
Am 17.01.22 um 11:09 schrieb Somalapuram, Amaranath:Any suggestion how we can notify user space during this situation.
[AMD Official Use Only]
-----Original Message-----
From: Koenig, Christian <Christian.Koenig@xxxxxxx>
Sent: Monday, January 17, 2022 3:33 PM
To: Somalapuram, Amaranath <Amaranath.Somalapuram@xxxxxxx>; amd-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: Deucher, Alexander <Alexander.Deucher@xxxxxxx>; Sharma, Shashank <Shashank.Sharma@xxxxxxx>
Subject: Re: [PATCH 2/2] drm/amdgpu: add AMDGPURESET uevent on AMD GPU reset
Am 17.01.22 um 11:01 schrieb Somalapuram, Amaranath:
[AMD Official Use Only]No, not really. kobject_uevent_env() will still allocate memory without GFP_ATOMIC.
-----Original Message-----
From: Koenig, Christian <Christian.Koenig@xxxxxxx>
Sent: Monday, January 17, 2022 12:57 PM
To: Somalapuram, Amaranath <Amaranath.Somalapuram@xxxxxxx>;
amd-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: Deucher, Alexander <Alexander.Deucher@xxxxxxx>; Sharma, Shashank
<Shashank.Sharma@xxxxxxx>
Subject: Re: [PATCH 2/2] drm/amdgpu: add AMDGPURESET uevent on AMD GPU
reset
Am 17.01.22 um 07:33 schrieb Somalapuram Amaranath:
AMDGPURESET uevent added to notify userspace, collect dump_stack andThis should probably go directly into the DRM subsystem.
trace
Signed-off-by: Somalapuram Amaranath <Amaranath.Somalapuram@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/nv.c | 45 +++++++++++++++++++++++++++++++++
1 file changed, 45 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/nv.c
b/drivers/gpu/drm/amd/amdgpu/nv.c index 2ec1ffb36b1f..b73147ae41fb
100644
--- a/drivers/gpu/drm/amd/amdgpu/nv.c
+++ b/drivers/gpu/drm/amd/amdgpu/nv.c
@@ -529,10 +529,55 @@ 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)
+{As I said this approach is a clear NAK. We can't allocate any memory when we do a reset.
+ char *event_string = "AMDGPURESET=1";
+ char *envp[2] = { event_string, NULL };
+
+ kobject_uevent_env(&dev->primary->kdev->kobj, KOBJ_CHANGE, envp);
Regards,
Christian.
Can I do something like this:
void drm_sysfs_reset_event(struct drm_device *dev)
{
- char *event_string = "AMDGPURESET=1";
- char *envp[2] = { event_string, NULL };
+ char **envp;
+
+ envp = kcalloc(2,sizeof(char *), GFP_ATOMIC);
+ envp[0] = kcalloc(30, sizeof(char), GFP_ATOMIC);
+ envp[1] = kcalloc(30, sizeof(char), GFP_ATOMIC);
I think the whole approach of using udev won't work for this.
Regards,
Christian.
I have tested it with sample applications:
Gpu reset:
sudo cat /sys/kernel/debug/dri/0/amdgpu_gpu_recover
And I never missed the AMDGPURESET=1 event in user space,
That's not the problem. Allocating memory when we need to do a reset can cause a *HARD* kernel deadlock.
This is absolutely not something we can do and Daniel even tried to add a few lockdep annotations for this.
So automated testing scripts will complain that this won't work.
Regards,
Christian.
Regards,
S.Amarnath
even with continues resets with sudo cat /sys/kernel/debug/dri/0/amdgpu_gpu_recover .
Regards,
S.Amarnath
+
+ strcpy(envp[0], "AMDGPURESET=1");
+ strcpy(envp[1], "");
+
kobject_uevent_env(&dev->primary->kdev->kobj, KOBJ_CHANGE,
envp);
+
+ kfree(envp[0]);
+ kfree(envp[1]);
+ kfree(envp);
}
Regards,
S.Amarnath
+}
+
+void amdgpu_reset_dumps(struct amdgpu_device *adev) {
+ struct drm_device *ddev = adev_to_drm(adev);
+ int r = 0, i;
+
+ /* original raven doesn't have full asic reset */
+ if ((adev->apu_flags & AMD_APU_IS_RAVEN) &&
+ !(adev->apu_flags & AMD_APU_IS_RAVEN2))
+ return;
+ for (i = 0; i < adev->num_ip_blocks; i++) {
+ if (!adev->ip_blocks[i].status.valid)
+ continue;
+ if (!adev->ip_blocks[i].version->funcs->reset_reg_dumps)
+ continue;
+ r = adev->ip_blocks[i].version->funcs->reset_reg_dumps(adev);
+
+ if (r)
+ DRM_ERROR("reset_reg_dumps of IP block <%s> failed %d\n",
+ adev->ip_blocks[i].version->funcs->name, r);
+ }
+
+ 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");
