[PATCH 1/2] drm: Add GPU reset sysfs event

[Sharma, Shashank]

I have a very limited understanding of PMC driver and its interfaces, so 
I would just go ahead and rely on Andrey's judgement/recommendation on 
this :)

- Shashank

On 3/8/2022 5:39 PM, Andrey Grodzovsky wrote:
> As long as PMC driver provides clear interface to retrieve the info 
> there should be no issue to call either amdgpu interface or PMC 
> interface using IS_APU (or something alike in the code)
> We probably should add a wrapper function around this logic in amdgpu.
> 
> Andrey
> 
> On 2022-03-08 11:36, Lazar, Lijo wrote:
>>
>> [AMD Official Use Only]
>>
>>
>> +Mario
>>
>> I guess that means the functionality needs to be present in amdgpu for 
>> APUs also. Presently, this is taken care by PMC driver for APUs.
>>
>> Thanks,
>> Lijo
>> ------------------------------------------------------------------------
>> *From:* amd-gfx <amd-gfx-bounces at lists.freedesktop.org> on behalf of 
>> Andrey Grodzovsky <andrey.grodzovsky at amd.com>
>> *Sent:* Tuesday, March 8, 2022 9:55:03 PM
>> *To:* Shashank Sharma <contactshashanksharma at gmail.com>; 
>> amd-gfx at lists.freedesktop.org <amd-gfx at lists.freedesktop.org>
>> *Cc:* Deucher, Alexander <Alexander.Deucher at amd.com>; Somalapuram, 
>> Amaranath <Amaranath.Somalapuram at amd.com>; Koenig, Christian 
>> <Christian.Koenig at amd.com>; Sharma, Shashank <Shashank.Sharma at amd.com>
>> *Subject:* Re: [PATCH 1/2] drm: Add GPU reset sysfs event
>>
>> On 2022-03-07 11:26, Shashank Sharma wrote:
>> > From: Shashank Sharma <shashank.sharma at amd.com>
>> >
>> > This patch adds a new sysfs event, which will indicate
>> > the userland about a GPU reset, and can also provide
>> > some information like:
>> > - which PID was involved in the GPU reset
>> > - what was the GPU status (using flags)
>> >
>> > This patch also introduces the first flag of the flags
>> > bitmap, which can be appended as and when required.
>>
>>
>> I am reminding again about another important piece of info which you 
>> can add
>> here and that is Smart Trace Buffer dump [1]. The buffer size is HW
>> specific but
>> from what I see there is no problem to just amend it as part of envp[]
>> initialization.
>> bellow.
>>
>> The interface to get the buffer is smu_stb_collect_info and usage can be
>> seen from
>> frebugfs interface in smu_stb_debugfs_open
>>
>> [1] - 
>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.spinics.net%2Flists%2Famd-gfx%2Fmsg70751.html&data=04%7C01%7Clijo.lazar%40amd.com%7C80bc3f07e2d0441d44a108da012036dc%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637823535167679490%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=53l7KlTf%2BICKkZkLVwFh6nRTjkAh%2FDpOat5DRoyKIx0%3D&reserved=0 
>> <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.spinics.net%2Flists%2Famd-gfx%2Fmsg70751.html&data=04%7C01%7Clijo.lazar%40amd.com%7C80bc3f07e2d0441d44a108da012036dc%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637823535167679490%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=53l7KlTf%2BICKkZkLVwFh6nRTjkAh%2FDpOat5DRoyKIx0%3D&reserved=0>
>>
>> Andrey
>>
>>
>> >
>> > Cc: Alexandar Deucher <alexander.deucher at amd.com>
>> > Cc: Christian Koenig <christian.koenig at amd.com>
>> > Signed-off-by: Shashank Sharma <shashank.sharma at amd.com>
>> > ---
>> >   drivers/gpu/drm/drm_sysfs.c | 24 ++++++++++++++++++++++++
>> >   include/drm/drm_sysfs.h     |  3 +++
>> >   2 files changed, 27 insertions(+)
>> >
>> > diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
>> > index 430e00b16eec..52a015161431 100644
>> > --- a/drivers/gpu/drm/drm_sysfs.c
>> > +++ b/drivers/gpu/drm/drm_sysfs.c
>> > @@ -409,6 +409,30 @@ void drm_sysfs_hotplug_event(struct drm_device 
>> *dev)
>> >   }
>> >   EXPORT_SYMBOL(drm_sysfs_hotplug_event);
>> >
>> > +/**
>> > + * drm_sysfs_reset_event - generate a DRM uevent to indicate GPU reset
>> > + * @dev: DRM device
>> > + * @pid: The process ID involve with the reset
>> > + * @flags: Any other information about the GPU status
>> > + *
>> > + * Send a uevent for the DRM device specified by @dev. This indicates
>> > + * user that a GPU reset has occurred, so that the interested client
>> > + * can take any recovery or profiling measure, when required.
>> > + */
>> > +void drm_sysfs_reset_event(struct drm_device *dev, uint64_t pid, 
>> uint32_t flags)
>> > +{
>> > +     unsigned char pid_str[21], flags_str[15];
>> > +     unsigned char reset_str[] = "RESET=1";
>> > +     char *envp[] = { reset_str, pid_str, flags_str, NULL };
>> > +
>> > +     DRM_DEBUG("generating reset event\n");
>> > +
>> > +     snprintf(pid_str, ARRAY_SIZE(pid_str), "PID=%lu", pid);
>> > +     snprintf(flags_str, ARRAY_SIZE(flags_str), "FLAGS=%u", flags);
>> > + kobject_uevent_env(&dev->primary->kdev->kobj, KOBJ_CHANGE, envp);
>> > +}
>> > +EXPORT_SYMBOL(drm_sysfs_reset_event);
>> > +
>> >   /**
>> >    * drm_sysfs_connector_hotplug_event - generate a DRM uevent for 
>> any connector
>> >    * change
>> > diff --git a/include/drm/drm_sysfs.h b/include/drm/drm_sysfs.h
>> > index 6273cac44e47..63f00fe8054c 100644
>> > --- a/include/drm/drm_sysfs.h
>> > +++ b/include/drm/drm_sysfs.h
>> > @@ -2,6 +2,8 @@
>> >   #ifndef _DRM_SYSFS_H_
>> >   #define _DRM_SYSFS_H_
>> >
>> > +#define DRM_GPU_RESET_FLAG_VRAM_VALID (1 << 0)
>> > +
>> >   struct drm_device;
>> >   struct device;
>> >   struct drm_connector;
>> > @@ -11,6 +13,7 @@ int drm_class_device_register(struct device *dev);
>> >   void drm_class_device_unregister(struct device *dev);
>> >
>> >   void drm_sysfs_hotplug_event(struct drm_device *dev);
>> > +void drm_sysfs_reset_event(struct drm_device *dev, uint64_t pid, 
>> uint32_t reset_flags);
>> >   void drm_sysfs_connector_hotplug_event(struct drm_connector 
>> *connector);
>> >   void drm_sysfs_connector_status_event(struct drm_connector *connector,
>> >                                      struct drm_property *property);