Issue observed:
- In GA10B, it was observed that after recovery happens
ELPG does not engage.
- It was because, after CE reset, when nvgpu_submit_twod test
was run to engage ELPG, IDLE_FLIPPED_PWR_OFF signal was asserted.
- This means that when ELPG was engaged (engine is in PWR_OFF),
some idle signal flips (becomes non-idle) and this causes
IDLE_SNAP. After IDLE_SNAP is hit, ELPG will not engage further.
- After debugging from WAVES, it was observed that:
LCE0/LCE1 are not done with the reset sequence.
- The state of these LCE is RESET0. A pri request (pri read
to NV_CE_PCE_MAP register in CE) is seen that kicks it out of
RESET0. After this state, it goes through few states to update
some internal states (states RESET1/RESET2/PCE_MAP etc) and then
eventually settles down to IDLE state.
Solution:
- Read ce_pce_map_r register in recovery sequence (after ce reset).
- It is observed that when this read is added recovery is complete
and post that when nvgpu_submit_two test is executed, ELPG is engaging.
- This means that a pri read is needed after CE reset so that it settles
to idle state properly and post that ELPG can engage properly.
Bug 200734258
Change-Id: I5bb84921ca62a740fde81ffe6c29ccde4ebb341b
Signed-off-by: Divya Singhatwaria <dsinghatwari@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2554493
Reviewed-by: svcacv <svcacv@nvidia.com>
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@nvidia.com>
Reviewed-by: svc-mobile-misra <svc-mobile-misra@nvidia.com>
Reviewed-by: svc-mobile-cert <svc-mobile-cert@nvidia.com>
Reviewed-by: svc_kernel_abi <svc_kernel_abi@nvidia.com>
Reviewed-by: Mahantesh Kumbar <mkumbar@nvidia.com>
Reviewed-by: Seema Khowala <seemaj@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
GVS: Gerrit_Virtual_Submit
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
