xgene_ahci_softreset(9)

✨ xgene_ahci_softreset(9) ✨

okay bestie, buckle up — this is the manual page for xgene_ahci_softreset(9) from the Kernel API Manual and it's genuinely iconic. it's giving "niche kernel driver lore" and i'm obsessed 💅

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🎀 NAME 🎀

xgene_ahci_softreset — literally just issues the softreset to the drive. that's it. that's the vibe. 💖

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🌸 SYNOPSIS 🌸

int xgene_ahci_softreset (struct ata_link *link , unsigned int *class ,
unsigned long deadline );

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🦋 ARGUMENTS 🦋

• link — the link to reset, bestie. this is the main character of the whole operation ✨
• class — a return value that tells you the class of the device. like a little gossip report on what kind of device we're dealing with 💁‍♀️
• deadline — the deadline in jiffies for the operation. yes, jiffies. no cap, that's the unit. ⏰

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💜 DESCRIPTION 💜

okay so this is where it gets juicy. due to H/W errata, the controller literally cannot save the PMP field it fetched from the command header before sending the H2D FIS. it's a hardware oopsie, not our fault. 😭

so when the device returns the PMP port field in the D2H FIS, there's a mismatch — and that mismatch results in command completion failure. not slay. 💀

the workaround? write the pmp value to the PxFBS.DEV field before issuing any command to PMP. periodt. and here's the algorithm to detect PMP, laid out step by step:

1. Save the PxFBS value 💾
2. Program PxFBS.DEV with the pmp value send by framework. Framework sends 0xF for both PMP/NON-PMP initially 🛠️
3. Issue softreset 🔄
4. If signature class is PMP goto 6 ➡️
5. restore the original PxFBS and goto 3 🔁
6. return 🏁

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🌈 SEE ALSO 🌈

• Kernel file ./drivers/ata/ahci_xgene.c
• xgene_ahci_poll_reg_val(9)
• xgene_ahci_restart_engine(9)
• xgene_ahci_qc_issue(9)
• xgene_ahci_read_id(9)
• xgene_ahci_do_hardreset(9)
• xgene_ahci_pmp_softreset(9)
• xgene_ahci_handle_broken_edge_irq(9)

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fr fr this whole thing lives in ./drivers/ata and it's lowkey a whole saga. go read the friends. iykyk 🫶

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and that's a wrap, bestie! this iconic page came from ./drivers/ata, dated October 2026, and it's literally the xgene_ahci_softreset(9) manual — slay, you made it to the end 💅✨🎀