Problem

When a runlist (command chain) times out, the driver was hardcoding error_index = 0, causing XRT to always report the first sub-command as the timed-out command — regardless of which sub-command actually hung. This made it impossible for userspace to identify the real offending command in a multi-command runlist.

Root Cause

In the timeout path of ve2_cmd_wait(), the driver unconditionally set cc->error_index = 0 with a comment stating this was intentional for the async/timeout case. Unlike the normal error path (where CERT writes completion status per slot), the timeout path fires before CERT has a chance to write per-slot completion. However, CERT does maintain a runlist_read_idx field in the handshake struct (offset 0x70) that tracks how many sub-commands have been processed, which was not being utilized.

Fix

Read runlist_read_idx from the CERT handshake memory via ve2_partition_read_privileged_mem() in the timeout path to determine the actual failing sub-command index. This mirrors the approach already used in the AIE4 driver (aie4_hwctx.c).

Changes

• ve2_hwctx.c — Replaced the hardcoded cc->error_index = 0 in the timeout path with a read of runlist_read_idx from CERT handshake memory (col 0, offset 0x70). The value is bounds-checked against cmd_count and falls back to 0 if out of range or if the privileged memory read fails. Added an XDNA_ERR log with the failing index, slot, and raw runlist_read_idx for diagnostics.
• ve2_host_queue.h — Renamed completion_status to runlist_read_idx in struct handshake to accurately reflect the field's purpose as defined by the CERT firmware.
• ve2_mgmt.c — Updated ve2_dump_debug_state() to print the renamed runlist_read_idx field.

Testing

• Tested with a mixed runlist containing a known-good ELF (simple_int8) and a timeout ELF (opcode_timeout) at configurable command indices. Verified that the driver now correctly reports the index of the hanging sub-command in both dmesg and the error_index returned to userspace via XRT.
• Also tested all the hw tests in ve2 hw.