[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]
>
>
>
> -----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 and
>> 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)
> This should probably go directly into the DRM subsystem.
>
>> +{
>> + char *event_string = "AMDGPURESET=1";
>> + char *envp[2] = { event_string, NULL };
>> +
>> + kobject_uevent_env(&dev->primary->kdev->kobj, KOBJ_CHANGE, envp);
> As I said this approach is a clear NAK. We can't allocate any memory when we do a reset.
>
> 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);
No, not really. kobject_uevent_env() will still allocate memory without 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,
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");
