[PATCH v3 3/3] drm/panthor: Report innocent group kill

[Steven Price]

On 29/10/2024 16:19, Boris Brezillon wrote:
> On Tue, 29 Oct 2024 16:29:12 +0100
> Boris Brezillon <boris.brezillon at collabora.com> wrote:
> 
>> Groups can be killed during a reset even though they did nothing wrong.
>> That usually happens when the FW is put in a bad state by other groups,
>> resulting in group suspension failures when the reset happens.
>>
>> If we end up in that situation, flag the group innocent and report
>> innocence through a new DRM_PANTHOR_GROUP_STATE flag.
>>
>> Bump the minor driver version to reflect the uAPI change.
>>
>> Changes in v3:
>> - Actually report innocence to userspace
>>
>> Changes in v2:
>> - New patch
>>
>> Signed-off-by: Boris Brezillon <boris.brezillon at collabora.com>
>> ---
>>  drivers/gpu/drm/panthor/panthor_drv.c   |  2 +-
>>  drivers/gpu/drm/panthor/panthor_sched.c | 18 ++++++++++++++++++
>>  include/uapi/drm/panthor_drm.h          |  9 +++++++++
>>  3 files changed, 28 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
>> index ac7e53f6e3f0..f1dff7e0173d 100644
>> --- a/drivers/gpu/drm/panthor/panthor_drv.c
>> +++ b/drivers/gpu/drm/panthor/panthor_drv.c
> 
> Forgot to update the changelog with:
> 
> --- a/drivers/gpu/drm/panthor/panthor_drv.c
> +++ b/drivers/gpu/drm/panthor/panthor_drv.c
> @@ -1493,6 +1493,7 @@ static void panthor_debugfs_init(struct drm_minor
> *minor)
>   * - 1.1 - adds DEV_QUERY_TIMESTAMP_INFO query
>   * - 1.2 - adds DEV_QUERY_GROUP_PRIORITIES_INFO query
>   *       - adds PANTHOR_GROUP_PRIORITY_REALTIME priority
> + * - 1.3 - adds DRM_PANTHOR_GROUP_STATE_INNOCENT flag
>   */
> 
> I'll send a v4 addressing that, but I'll probably queue the first two
> patches to drm-misc-fixes first.

With the changelog update you can add:

Reviewed-by: Steven Price <steven.price at arm.com>

Thanks,
Steve

>> @@ -1507,7 +1507,7 @@ static const struct drm_driver panthor_drm_driver = {
>>  	.desc = "Panthor DRM driver",
>>  	.date = "20230801",
>>  	.major = 1,
>> -	.minor = 2,
>> +	.minor = 3,
>>  
>>  	.gem_create_object = panthor_gem_create_object,
>>  	.gem_prime_import_sg_table = drm_gem_shmem_prime_import_sg_table,
>> diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
>> index ef4bec7ff9c7..97ed5fe5a191 100644
>> --- a/drivers/gpu/drm/panthor/panthor_sched.c
>> +++ b/drivers/gpu/drm/panthor/panthor_sched.c
>> @@ -610,6 +610,16 @@ struct panthor_group {
>>  	 */
>>  	bool timedout;
>>  
>> +	/**
>> +	 * @innocent: True when the group becomes unusable because the group suspension
>> +	 * failed during a reset.
>> +	 *
>> +	 * Sometimes the FW was put in a bad state by other groups, causing the group
>> +	 * suspension happening in the reset path to fail. In that case, we consider the
>> +	 * group innocent.
>> +	 */
>> +	bool innocent;
>> +
>>  	/**
>>  	 * @syncobjs: Pool of per-queue synchronization objects.
>>  	 *
>> @@ -2690,6 +2700,12 @@ void panthor_sched_suspend(struct panthor_device *ptdev)
>>  			u32 csg_id = ffs(slot_mask) - 1;
>>  			struct panthor_csg_slot *csg_slot = &sched->csg_slots[csg_id];
>>  
>> +			/* If the group was still usable before that point, we consider
>> +			 * it innocent.
>> +			 */
>> +			if (group_can_run(csg_slot->group))
>> +				csg_slot->group->innocent = true;
>> +
>>  			/* We consider group suspension failures as fatal and flag the
>>  			 * group as unusable by setting timedout=true.
>>  			 */
>> @@ -3570,6 +3586,8 @@ int panthor_group_get_state(struct panthor_file *pfile,
>>  		get_state->state |= DRM_PANTHOR_GROUP_STATE_FATAL_FAULT;
>>  		get_state->fatal_queues = group->fatal_queues;
>>  	}
>> +	if (group->innocent)
>> +		get_state->state |= DRM_PANTHOR_GROUP_STATE_INNOCENT;
>>  	mutex_unlock(&sched->lock);
>>  
>>  	group_put(group);
>> diff --git a/include/uapi/drm/panthor_drm.h b/include/uapi/drm/panthor_drm.h
>> index 87c9cb555dd1..b99763cbae48 100644
>> --- a/include/uapi/drm/panthor_drm.h
>> +++ b/include/uapi/drm/panthor_drm.h
>> @@ -923,6 +923,15 @@ enum drm_panthor_group_state_flags {
>>  	 * When a group ends up with this flag set, no jobs can be submitted to its queues.
>>  	 */
>>  	DRM_PANTHOR_GROUP_STATE_FATAL_FAULT = 1 << 1,
>> +
>> +	/**
>> +	 * @DRM_PANTHOR_GROUP_STATE_INNOCENT: Group was killed during a reset caused by other
>> +	 * groups.
>> +	 *
>> +	 * This flag can only be set if DRM_PANTHOR_GROUP_STATE_TIMEDOUT is set and
>> +	 * DRM_PANTHOR_GROUP_STATE_FATAL_FAULT is not.
>> +	 */
>> +	DRM_PANTHOR_GROUP_STATE_INNOCENT = 1 << 2,
>>  };
>>  
>>  /**
>