Episode: MI25 Driver Interface Study

EPISODE-GOAL

Understand the Linux driver for the AMD MI25 GPU and document the externally exposed kernel interfaces (sysfs, hwmon, debugfs) that a fan-control service can use.

EPISODE-ACCEPTANCE

• Does the document identify the exact driver version and source tree that runs the MI25 on beast.lan?
• Does the document map every hwmon attribute relevant to fan control (sensors, pwm1*, fan1*) with its semantics and a source citation?
• Does the document map the device sysfs surface (power_dpm_*, pp_*, mem_info_*, busy/voltage files) with source citations?
• Does the document state which debugfs interfaces exist and why they are unavailable on beast.lan (debugfs not mounted)?
• Does the document confirm whether amdgpu exposes anything under /proc?
• Does the document trace the fan-control path from a pwm1 write to the powerplay/SMU layer for Vega 10, with file:line citations?
• Is every live-state fact verified on beast.lan and marked with its verification date?
• Is the source drift between the DKMS 6.19.14 source and the local mainline 7.2/7.3 tree recorded?

EPISODE-RISKS

• Is the local mainline tree close enough to the running DKMS driver that conclusions drawn from it hold for the live system?
• Does writing to pwm1 on the live MI25 change the fan as the driver source claims?
• Is the sensor-to-temperature mapping (edge/junction/mem) stable across driver versions?

EPISODE-TASKS

• Identify the running driver: module version, source tree, module parameters, kernel version.
• Document the hwmon surface from amdgpu_pm.c in both source trees.
• Document the device sysfs surface from the driver source and live /sys.
• Document debugfs interfaces from the driver source and confirm the mount state on beast.lan.
• Confirm the /proc situation for amdgpu on beast.lan.
• Trace the fan-control call path for Vega 10 from pwm1 write to the SMU.
• Cross-check the DKMS 6.19.14 source against the local mainline tree and record drift.
• Verify every live-state fact on beast.lan and date it.
• Write the document, run make test, commit, and write a record.

EPISODE-OUTPUT

A rough draft of documents/05-mi25-driver-interfaces.md for human review, plus the record of the episode in records/.

EPISODE-FILES

• prompts/episodes/02-mi25-driver-interface-study.md — new
• documents/05-mi25-driver-interfaces.md — new
• records/02-mi25-driver-interface-study.md — new
• TODO.md — modify