MSTLINK(1)

💅 MSTLINK — the mstlink girlies' guide (section 1, User Commands)

okay bestie, sit down, hydrate, because we're doing link debugging and we're doing it right. This is the manual for mstlink, a user command, and it's giving main character energy from the very first line.

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✨ NAME ✨

mstlink — check and debug link status and issues related to them 💖

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🦋 SYNOPSIS 🦋

mstlink [OPTIONS]

that's it. that's the whole vibe. options go in, diagnostics come out. 🎀

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🌸 DESCRIPTION 🌸

So, the mlxlink tool — yes, mlxlink, the page says mlxlink, we're quoting it, no notes — is used to check and debug link status and issues related to them. That's the whole job. 🔥

And it's not picky about which link, bestie. The tool can be used on different links and cables, including:

• passive cables
• active cables
• transceiver
• backplane

so basically whatever cable situation you've got going on, it's got you. 💜

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🌈 OPTIONS 🌈

general flags first, then the queries, then the commands. we do not skip. we do not summarise. we are thorough in this house. 👑

• -h, --help — Display help message. (the "hello, what is this" button 🫶)
• -v, --version — Display version info.
• -d, --device <device> — Perform operation for a specified mst device.
• -p, --port <port_number_or_list> — Port Number, or a comma-separated list of ports (e.g. 1,2,3). Heads up though: a list is currently supported only with -a/--port_state. 💀
• --port_type <port_type> — Port Type [NETWORK(Default)/PCIE]. default is NETWORK, iykyk.
• --depth <depth> — depth level of the DUT of some hierarchy (PCIE only).
• --pcie_index <pcie_index> — PCIe index number (Internal domain index) (PCIE only).
• --node <node> — the node within each depth (PCIE only).
• --json — Print the output in json format. for the girlies who pipe things into other things. ✨

🧚 QUERIES (aka the "just tell me things" era)

• --show_links — Show valid PCIe links (PCIE only).
• -m, --show_module — Show Module Info. And ooh, plot twist: when combined with --cable, shows the module pre-coding info (Host/Line Tx/Rx operational status). obsessed.
• -c, --show_counters — Show Physical Counters and BER Info.
• -e, --show_eye — Show Eye Opening Info. 👁️ (pun intended, no I will not apologise)
• --show_fec — Show FEC Capabilities.
• --show_serdes_tx — Show Transmitter Info.
• --show_device — General Device Info.
• --show_ber_monitor — Show BER Monitor Info — but not supported for HCA, so don't come for me if your HCA says no. 🙈
• --show_external_phy — Show External PHY Info.

💅 COMMANDS (aka the "okay now change things" era)

• -a, --port_state <port_state> — Configure Port State [UP(up)/DN(down)/TG(toggle)].
• -s, --speeds <speeds> — Configure Speeds [speed1,speed2,...].
• --link_mode_force — Configure Link Mode Force (Disable AN).
• -l, --loopback <loopback> — Configure Loopback Mode [NO(no loopback)/PH(phy loopback)/EX(external loopback)].
• -k, --fec <fec_override> — Configure FEC [AU(Auto)/NF(No-FEC)/FC(FireCode FEC)/RS(RS-FEC)].
• --fec_speed <fec_speed> — Speed to Configure FEC [100G/50G/25G/...] (Default is Active Speed).
• --serdes_tx <params> — Configure Transmitter Parameters [polarity,ob_tap0,...].
• --serdes_tx_lane <transmitter_lane> — Transmitter Lane to Set (Optional - Default All Lanes).
• --database — Save Transmitter Configuration for Current Speed Permanently (Optional).
• --test_mode <prbs_mode> — Physical Test Mode Configuration [EN(enable)/DS(disable)/TU(perform tuning)].
• --rx_prbs <rx_prbs_mode> — RX PRBS Mode [PRBS31(Default)/PRBS7/...] (Optional - Default PRBS31).
• --tx_prbs <tx_prbs_mode> — TX PRBS Mode [PRBS31(Default)/PRBS7/...] (Optional - Default PRBS31).
• --rx_rate <rx_lane_rate> — RX Lane Rate [EDR(Default)/25G/10G/...] (Optional - Default 25G).
• --tx_rate <tx_lane_rate> — TX Lane Rate [EDR(Default)/25G/10G/...] (Optional - Default 25G).
• -b, --ber_collect <csv_file> — Port Extended Information Collection [CSV File].
• --ber_limit <limit_criteria> — BER Limit Criteria [Nominal(Default)/Corner/Drift] (Optional - Default Nominal).
• --iteration <iteration> — Iteration Number of BER Collection.
• --pc — Clear Counters.
• --set_external_phy — Set External PHY — not supported for HCA, again, don't @ me. 🫶
• --twisted_pair_force_mode <twisted_pair_force_mode> — Twisted Pair Force Mode [MA(Master)/SL(Slave)].

Also yes, the page literally lists the default for --rx_rate as EDR(Default) while the parenthetical says Default 25G. We are copying that verbatim because the rule is we keep every single detail, no cap. 😭

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⭐ EXAMPLES ⭐

this is the part where it gets real. copy these, they're cute.

get info of <device>, <port_number>:

mstlink -d <device> -p <port_number>

get info of <device>, <port_number> and BER Counters:

mstlink -d <device> -p <port_number> -c

get info of <device>, <port_number> and Transmitter Parameters:

mstlink -d <device> -p <port_number> --show_serdes_tx

Configure Port State:

mstlink -d <device> -p <port_number> --port_state UP

mstlink -d <device> -p 1,2,3 --port_state DN

(see? the comma list, and see? it's with --port_state. told you. 💅)

Configure Port Speeds:

mstlink -d <device> -p <port_number> --speeds 25G,50G,100G

Configure FEC:

mstlink -d <device> -p <port_number> --fec RS

Configure Port for Physical Test Mode:

mstlink -d <device> -p <port_number> --test_mode EN (--rx_prbs PRBS31 --rx_rate 25G --tx_prbs PRBS7 --tx_rate 10G)

Perform PRBS Tuning:

mstlink -d <device> -p <port_number> --test_mode TU

Configure Transmitter Parameters (on lane, to database):

mstlink -d <device> -p <port_number> (--serdes_tx_lane <lane number>) (--database) \
  --serdes_tx <polarity>,<ob_tap0>,<ob_tap1>,<ob_tap2>,<ob_bias>,<ob_preemp_mode>

PCIe queries (supported on HCA, CPU and Switches that advertise PCIe management):

List valid PCIe links:

mstlink -d <device> --port_type PCIE --show_links

Show PCIe operational info for a specific link:

mstlink -d <device> --port_type PCIE --depth <d> --pcie_index <i> --node <n>

Show PCIe BER/MPCNT counters:

mstlink -d <device> --port_type PCIE -c

Collect amBER for PCIe links:

mstlink -d <device> --port_type PCIE --amber_collect <file.csv>

Note: --pcie_error_injection is supported on HCA devices only. 🎀

(and yes, --amber_collect up there is exactly what the page says. keeping it character for character, bestie, that's the assignment. 🫶)

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🎀 SEE ALSO 🎀

• mstflint(1) — the sibling. go say hi. 👑

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and that's the whole page, bestie. every flag, every default, every bracket, every (PCIE only), all of it, preserved like a pressed flower. 🌸

this page comes from mstflint, dated March 2020. slay, periodt, go debug your links. 💖✨🦋