STRUCT LOADER_MSG_HDR(9)

💖 struct loader_msg_hdr — the Kernel API Manual moment 🎀

okay bestie, so we're looking at struct loader_msg_hdr from the Kernel API Manual and honestly? it's giving "small but iconic." it's literally the Header for ISH Loader commands — like the little name tag every command wears so everyone knows who's who. 🦋

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✨ SYNOPSIS ✨

struct loader_msg_hdr {
    u8 command;
    u8 reserved[2];
    u8 status;
 };

that's the whole thing. four fields. no cap, that's it. (yes the closing brace has a lil space before it in the original, we're keeping it exactly like that, we don't touch the source 💅)

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🌸 Members 🌸

• command — straight up the LOADER_CMD* commands. and bestie, plot twist: bit 7 is the response. so that one byte is doing double duty, main character energy fr fr.
• reserved — reserved space. it's just... vibing there. don't touch it. it has a job (sitting there) and it's doing it. 🙈
• status — the command response status. non 0 means error condition — so like, if it's not zero, something's wrong, periodt. 😭

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🌈 Description 🌈

so here's the vibe check: this structure is used as the header for every command/data sent/received between the Host driver and the ISH Shim firmware loader. every single one. it's the header of headers, the group chat admin of the loader protocol, lowkey obsessed with how consistent it is. ⭐

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🔥 SEE ALSO 🔥

y'all need the whole crew? here they are, in order, besties:

• Kernel file ./drivers/hid/intel-ish-hid/ishtp-fw-loader.c
• enum ish_loader_commands(9)
• struct response_info(9)
• get_firmware_variant(9)
• loader_cl_send(9)
• process_recv(9)
• loader_cl_event_cb(9)
• ish_query_loader_prop(9)
• ish_fw_xfer_ishtp(9)
• ish_fw_xfer_direct_dma(9)
• ish_fw_start(9)
• load_fw_from_host(9)
• loader_init(9)
• loader_ishtp_cl_probe(9)
• loader_ishtp_cl_remove(9)
• loader_ishtp_cl_reset(9)

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ngl, if you're poking at ISH Loader commands, read these before you start typing. iykyk. 🫶

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that's the whole page, bestie 💜 this one came from ./drivers/hid/intel-ish-hid, dated October 2026 — go off, kernel docs, you ate. ✨👑