create_pbc(9)

💅 create_pbc(9) — like, the whole glow-up

okay so bestie, welcome to create_pbc(9), straight out of the Kernel API Manual ✨ this is the page where we build a PBC for transmission, and honestly? iconic behavior. let's get into it 🎀

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✨ SYNOPSIS ✨

u64 create_pbc (struct hfi1_pportdata *ppd , u64 flags , int srate_mbs ,
u32 vl , u32 dw_len );

like, that's the whole signature, no cap 🫶

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🌸 ARGUMENTS 🌸

• ppd — info of physical Hfi port 💖 like the little ID card for the hardware port
• flags — special case flags or-ed in built pbc 🔥 you're OR-ing these bad boys right into the PBC
• srate_mbs — static rate ⭐
• vl — vl 👑 (yes, that's the whole description, and honestly? respect for the brevity)
• dw_len — dword length (header words + data words + pbc words) 🦋 so it's the full dword count, all three chunks added up, not just one of them, iykyk

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💜 DESCRIPTION 💜

Create a PBC with the given flags, rate, VL, and length. periodt. that's the vibe — you hand it the flags, the rate, the VL, and the length, and it builds you a PBC 🌈

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🙈 NOTE 🙈

ok so this is the important bit, don't skip it bestie 😭 the PBC created will not insert any HCRC — all callers but one are for verbs, which does not use this PSM feature. the lone other caller is for the diagnostic interface, which calls this if the user does not supply their own PBC. so like... no HCRC, fr fr. one (1) exception to the verbs-only situation, and it's the diagnostics one 🩷

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🧚 SEE ALSO 🧚

Kernel file ./drivers/infiniband/hw/hfi1/chip.c — go read it, it's giving main character energy 👑

and the whole friend group 💅:

• hfi1_addr_from_offset(9)
• read_csr(9)
• write_csr(9)
• get_csr_addr(9)
• update_xmit_counters(9)
• apply_link_downgrade_policy(9)
• is_rcv_avail_int(9)
• is_rcv_urgent_int(9)
• general_interrupt(9)
• hfi1_rcd_eoi_intr(9)
• hfi1_netdev_rx_napi(9)
• data_vls_operational(9)
• encode_rcv_header_entry_size(9)
• hfi1_validate_rcvhdrcnt(9)
• set_hdrq_regs(9)
• update_statusp(9)
• wait_logical_linkstate(9)
• read_mod_write(9)
• set_intr_bits(9)
• set_up_interrupts(9)
• hfi1_get_qp_map(9)
• init_qpmap_table(9)
• init_qos(9)
• hfi1_init_dd(9)

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🎀 sign-off 🎀

this masterpiece lives in ./drivers/infiniband/hw/hfi1 and it's dated October 2026 — slay, future girlies will still be reading this 💖✨ bye bestie, go build that PBC 🦋