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464de27507
- When DISALLOW cmd is sent from driver to PMU the actual
completion of the disallow will be acknowledged by PMU
via a PG EVENT: ASYNC_CMD_RESP.
- Disallow needs a delayed ACK from PMU in order to disable
the ELPG.
- If ELPG is already engaged, the DISALLOW cmd will trigger
ELPG exit and then transition to PMU_PG_STATE_DISALLOW.
- After this whole process is completed, PMU will send
DISALLOW_ACK through ASYNC_CMD_RESP msg.
- After disallow command is sent from the driver, NvGPU driver
waits/polls for disallow command ack. This is sent immediately
by msg framework of PMU.
- Then, the driver will poll/wait for ASYNC_CMD_RESP event which
is the delayed DISALLOW ACK.
- The driver captures the ASYNC_CMD_RESP sent from PMU.
- set disallow_state to ELPG_OFF.
- If the driver does not wait/poll for this delayed disallow
ack from PMU, it can result in erros as PMU is still
processing DISALLOW cmd but the driver progressed further.
Bug 3580271
Change-Id: I332180c05b6a398107f065d54e9718b7038fb1b2
Signed-off-by: Divya <dsinghatwari@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2689500
(cherry picked from commit fb019bf43a)
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2694312
Reviewed-by: Sagar Kamble <skamble@nvidia.com>
Reviewed-by: Vijayakumar Subbu <vsubbu@nvidia.com>
GVS: Gerrit_Virtual_Submit