The current implementation of drm_sched_start uses a hardcoded
-ECANCELED to dispose of a job when the parent/hw fence is NULL.
This results in drm_sched_job_done being called with -ECANCELED for
each job with a NULL parent in the pending list, making it difficult
to distinguish between recovery methods, whether a queue reset or a
full GPU reset was used.

To improve this, we first try a soft recovery for timeout jobs and
use the error code -ENODATA. If soft recovery fails, we proceed with
a queue reset, where the error code remains -ENODATA for the job.
Finally, for a full GPU reset, we use error codes -ECANCELED or
-ETIME. This patch adds an error code parameter to drm_sched_start,
allowing us to differentiate between queue reset and GPU reset
failures. This enables user mode and test applications to validate
the expected correctness of the requested operation. After a
successful queue reset, the only way to continue normal operation is
to call drm_sched_job_done with the specific error code -ENODATA.

v1: Initial implementation by Jesse utilized amdgpu_device_lock_reset_domain
    and amdgpu_device_unlock_reset_domain to allow user mode to track
    the queue reset status and distinguish between queue reset and
    GPU reset.
v2: Christian suggested using the error codes -ENODATA for queue reset
    and -ECANCELED or -ETIME for GPU reset, returned to
    amdgpu_cs_wait_ioctl.
v3: To meet the requirements, we introduce a new function
    drm_sched_start_ex with an additional parameter to set
    dma_fence_set_error, allowing us to handle the specific error
    codes appropriately and dispose of bad jobs with the selected
    error code depending on whether it was a queue reset or GPU reset.
v4: Alex suggested using a new name, drm_sched_start_with_recovery_error,
    which more accurately describes the function's purpose.
    Additionally, it was recommended to add documentation details
    about the new method.
v5: Fixed declaration of new function drm_sched_start_with_recovery_error.(Alex)
v6 (chk): rebase on upstream changes, cleanup the commit message,
          drop the new function again and update all callers,
          apply the errno also to scheduler fences with hw fences
v7 (chk): rebased

Signed-off-by: Jesse Zhang <Jesse.Zhang@amd.com>
Signed-off-by: Vitaly Prosyak <vitaly.prosyak@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240826122541.85663-1-christian.koenig@amd.com