tpm_transmit(9)

💖 tpm_transmit(9) — from the Kernel API Manual, bestie 💖

okay so welcome to the group chat, this is tpm_transmit from section 9 of the Kernel API Manual and honestly she's lowkey a legend 🫶

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✨ NAME ✨

tpm_transmit — the internal kernel interface for transmitting TPM commands, no cap 💅

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🌸 SYNOPSIS 🌸

ssize_t tpm_transmit (struct tpm_chip *chip , u8 *buf , size_t bufsiz );

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🎀 ARGUMENTS 🎀

• chip — a TPM chip to use, like, the actual chip you're talking to 🦋
• buf — a TPM command buffer. this is where the command lives fr
• bufsiz — length of the TPM command buffer. gotta know how big buf is, obviously 💜

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🔥 DESCRIPTION 🔥

so what she actually does: she's a wrapper around tpm_try_transmit 💫 and the way that she handles TPM2_RC_RETRY returns from the TPM is genuinely iconic — she retransmits the command after a delay, up to a maximum wait of TPM2_DURATION_LONG ⭐

bestie, important lore: TPM 1.x never returns TPM2_RC_RETRY, so this whole retry logic is TPM 2.0 only 👑 don't come for her about 1.x, she doesn't play that game

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🌈 RETURN 🌈

• The response length — OK 💖
• -errno — A system error 😭

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🧚 SEE ALSO 🧚

• Kernel file ./drivers/char/tpm/tpm-interface.c
• tpm_calc_ordinal_duration(9)
• tpm_transmit_cmd(9)
• tpm_is_tpm2(9)
• tpm_pcr_read(9)
• tpm_pcr_extend(9)
• tpm_get_random(9)

all of these are her besties, go say hi 💕

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and that's the whole page, periodt 🎀 this came out of ./drivers/char/tpm and is dated October 2026 — mwah, love u, go transmit some commands responsibly ✨💜