Add display_transcoder.rs — TRANS_DDI_FUNC_CTL programming for
platforms with separate transcoders (Xe2/Gen12+ where pipe != transcoder).
- Transcoder::configure(): program TRANS_DDI_FUNC_CTL (0x60400 +
0x1000 per transcoder) with DDI select, DP/HDMI mode select,
port width (1/2/4 lanes), and enable bit
- disable(): clear TRANS_DDI_FUNC_ENABLE
- is_enabled(): check TRANS_DDI_FUNC_ENABLE status
- EDP transcoder at 0x6F400 for pipe 3
Wire into IntelDriver::set_crtc — configure transcoder after
modesetting, using pipe.port and TransDdiMode::Dp with 4 lanes.
Only active when has_separate_transcoder == true.
Linux reference: intel_ddi.c (TRANS_DDI_FUNC_CTL programming)
vasilito
b21494dacf