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

[Andrey Grodzovsky <andrey.grodzovsky@xxxxxxx>]

On 2022-03-08 11:35, Sharma, Shashank wrote:
> On 3/8/2022 5:25 PM, Andrey Grodzovsky wrote:
> > On 2022-03-07 11:26, Shashank Sharma wrote:
> > > From: Shashank Sharma <shashank.sharma@xxxxxxx>
> > >
> > > 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://www.spinics.net/lists/amd-gfx/msg70751.html
>
> Noted Andrey, thank for the reminder. As you can see, this patch is 
> going into DRM layer, so as of now we are accommodating the PID and 
> VRAM validity information, which is common to all the DRM drivers (not 
> only AMDGPU). But as a next step, we will extend this interface to 
> provide driver specific custom data as well,  and that is where we 
> will start digging into STB.
> - Shashank


Got it.

Andrey


> > Andrey
> >
> >
> > > Cc: Alexandar Deucher <alexander.deucher@xxxxxxx>
> > > Cc: Christian Koenig <christian.koenig@xxxxxxx>
> > > Signed-off-by: Shashank Sharma <shashank.sharma@xxxxxxx>
> > > ---
> > >   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);