Add dp_aux.rs implementing DisplayPort AUX channel for EDID reads
and DPCD capability queries. Critical for Xe2/Arrow Lake which lacks
GMBUS and must use DP AUX for all EDID operations.
- dp_aux.rs: DpAux struct with per-port AUX channel (CTL at 0x64010,
DATA at 0x64014, 0x100 stride). Implements do_transfer() with
native read/write and I2C-over-AUX protocols, wait_for_completion()
with busy/done/timeout/receive_error detection, read_dpcd() for
DPCD register access, read_dpcd_caps() for capability enumeration,
and read_edid() via I2C-over-AUX (MOT-based segmented reads)
- mod.rs: declare dp_aux module, add DpAux import, add dp_aux: Vec<DpAux>
field to IntelDriver, initialize one DpAux per port in constructor
Linux reference: intel_dp_aux.c, intel_dp_aux_regs.h
Compiled: 0 new errors (pre-existing daemon errors unrelated)
vasilito
49084b8fbe