Release v5.0 · nuxcodes/rockpod

v5.0

Rewrote source mode audio path — USB ISR now pulls PCM data directly from the mixer via double-buffered DMA, replacing the ring buffer approach. Eliminates buffering latency and underflow-related clicks.
Skipped EP0 IN flush during ISO streaming to avoid busy-waiting on AHB idle that could stall active audio transfers.
Playback pauses automatically when the dock disconnects or powers off.
Added intermediate clocking level (CPU 108MHz, AHB 108MHz) for USB audio use alongside the existing boost/unboost levels.

Fixed non-authenticating accessories (legacy Identify) being permanently blocked — grant auth state immediately when no authentication is requested.
Fixed first iAP packet being dropped on USB HID accessories by allocating buffers synchronously during transport activation instead of deferring via IAP_EV_MALLOC.
Strip unsupported lingoes from the accessory's identification request instead of rejecting the entire connection. Docks like the Onkyo request lingoes (Microphone, USB Host, etc.) that Rockbox doesn't support — masking them out lets the accessory work with the supported subset.
Accept unsupported preference classes (video, etc.) and return preference=0 instead of rejecting — accessories disconnect if preferences are rejected.
Trigger digital audio init for both legacy-auth and IDPS-auth docks (previously only IDPS).

Fixed backlight dim and LCD autosleep not working during cover art browsing. PictureFlow had its own backlight management that overrode the system timers — removed it so the standard backlight/sleep settings apply.

Added USB audio source mode diagnostics: streaming state, sampling frequency, source underflows, frames sent, ISO incomplete transfer count.

Periodic ~1s audio pop on MFi docks that poll iAP status during streaming (e.g. Onkyo ND-S1). Various workarounds were attempted (USB IRQ priority, DMA arbiter tuning, HID TX serialization) but did not fully resolve the issue. Fixed in v5.1.