test(hw, adrv9371): update TODO with Mykonos-vs-Talise finding

Reverted commits b117949 / 5222208 showed that profile-reload
alone is not sufficient to unblock AD9371 DMA on bq: writing a
Mykonos profile to ``profile_config`` is accepted, but JESD204 RX
leaves ``Link status: DATA`` and never returns within a 30 s poll,
whereas Talise on ADRV9009 relocks in ~3 s.

Extend the TODO block with the ruled-out attempts and the likely
next investigation direction (Mykonos ``ensm_mode`` / calibration
attrs, or explicit RX enable via ``adi.ad9371``).  Keeping the
AD9371 test at JESD-DATA + dmesg-health parity with the other hw
tests until a board-specific capture recipe is worked out — this
PR does not try to fix the gap.

Author: tfcollins

test/hw/test_adrv9371_zc706_hw.py

@@ -152,13 +152,33 @@ def test_adrv9371_zc706_xsa_hw(board, built_kernel_image_zynq, tmp_path):
         f"No AD9528 clock device found. Devices: {sorted(found)}"
     )
 
-    # TODO(adrv9371-capture): restore once the test loads a Talise
-    # profile post-boot.  AD9371 DMA doesn't deliver samples until the
-    # driver has a profile written, and ``test_adrv9371_zc706_hw`` does
-    # not yet write one (cf. ``test_adrv9009_zcu102_hw`` which does).
-    # Without the profile ``assert_rx_capture_valid`` legitimately
-    # times out on ``ad_ip_jesd204_tpl_adc``; enabling it would turn
-    # a known-config gap into a red CI.
+    # TODO(adrv9371-capture): data-path smoke test is deferred on
+    # AD9371/ZC706 until the out-of-the-box design delivers samples
+    # from the TPL core without runtime intervention.
+    #
+    # Investigated and ruled out (commits b117949, 5222208 — both
+    # reverted):
+    #
+    # - Mirroring the adrv9009 post-boot Talise write with a Mykonos
+    #   profile does *not* unblock DMA here.  The profile file
+    #   (``ad9371_5/profile_TxBW100_ORxBW100_RxBW100.txt``, 2123 bytes,
+    #   deviceClock_kHz=122880 matching the AD9528 VCXO) is accepted
+    #   by the driver at ``/sys/.../iio:device2/profile_config`` — but
+    #   immediately after the write the JESD204 RX link leaves
+    #   ``Link status: DATA`` and does not return within a 30 s poll.
+    #   Talise re-inits and JESD-relocks on ``profile_config`` write;
+    #   Mykonos on AD9371 does not do the same JESD restart, leaving
+    #   the link down after any runtime profile change.
+    #
+    # - On initial boot (before any write), JESD is in DATA but
+    #   ``iio.Buffer.refill()`` on ``ad_ip_jesd204_tpl_adc`` times
+    #   out, i.e. the TPL DMA isn't streaming despite a locked link.
+    #
+    # The next investigation step is a board-specific capture recipe
+    # (possibly via the Mykonos driver's ``ensm_mode`` / calibration
+    # attributes, or via pyadi-iio's ``adi.ad9371`` helpers with
+    # explicit RX enable) — out of scope for the data-capture-smoke
+    # addition in this PR.
 
 
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