xgene_ahci_pmp_softreset(9)

💅 NAME

okay bestie, this is xgene_ahci_pmp_softreset(9), straight out of the Kernel API Manual — and its whole main-character job is to issue the softreset to the drives connected to Port Multiplier. slay.

✨ SYNOPSIS

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

🫶 ARGUMENTS

• link — link to reset
• class — Return value to indicate class of device
• deadline — deadline jiffies for the operation

🧚 DESCRIPTION

so here’s the tea: due to H/W errata, the controller is unable to save the PMP field fetched from command header before sending the H2D FIS. 😭 when the device returns the PMP port field in the D2H FIS, there is a mismatch and results in command completion failure. not cute.

the workaround is literally to write the pmp value to PxFBS.DEV field before issuing any command to PMP. periodt. 💅

🌈 SEE ALSO

Kernel file ./drivers/ata/ahci_xgene.c is the home base, and these are the see-also besties:

• 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_softreset(9)
• xgene_ahci_handle_broken_edge_irq(9)

okay that’s the whole page 💖 cute sign-off: source/version ./drivers/ata, date October 2026. bye bestie 🫶