lowRISC / lowRISC/ibex

riscv_debug_wfi_test failed

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Type:Bug
Dominant language
SystemVerilog
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Description

Hi, When I use the make TEST=riscv_debug_wfi_test SEED=27946 the case 27948 will failed due to timeout.

It's failed because the second instruction of main function is wfi instruction, but the task check_stimulus of the class core_ibex_debug_wfi_test is start later than wfi instruction execution( after wait_for_setup, it also wait another 50 cycles), so it will never wait for wfi instructions until timeout.

Does anyone know how to solve this issue? My current approach is to comment \\clk_vif.wait_clks(50); at line 456 of core_ibex_test_lib.sv, and can pass, but not sure if it will affect other cases.

Tool: vcs o-2018.09-SP2-9
Config: small

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Research direction

Reproduce the failure with make TEST=riscv_debug_wfi_test SEED=27946 and inspect core_ibex_test_lib.sv around line 456. Trace core_ibex_debug_wfi_test, check_stimulus, and wait_for_setup to understand the timing of the extra 50-cycle wait. Done means the WFI test passes without causing other cases to fail.

Written by the indexing model from the issue text.

Assessment

Domain
testing-qa
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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