DualShock 4 BT Driver + ROM Library CRC32 Scanner + Two-Level Browser — Player Experience Complete

Two "player experience" commits round out the 0.6.0 feature set for the RetroPie fleet. drivers/input/bt-hid/ds4_bt.sg (sigil-drivers 183a71f) adds the Sony DualShock 4 Bluetooth HID driver — both DS4 v1 (054C:05C4) and v2 (054C:09CC), 77-byte HID report 0x11, full button/axis/D-pad/touchpad surface, synthetic inject + snap/restore rollback, 21 checks PASS. tools/rom_scan.py + ui/library_scene.sg (sigil-retropie 960b9bd) deliver the ROM library: a MAME/No-Intro CRC32 scanner that identifies and verifies ROMs against official dat files, generates a compile-time Sigil catalog (lib/rom_catalog_gen.sg), and drives a two-level launcher UI (4×5 card grid, L1/R1 system navigation, year/publisher/verified badge).

DualShock 4 BT driver (183a71f — sigil-drivers)

Sony DualShock 4 is the most-used controller for PlayStation-era RetroPie titles (PS1, PS2, and PS4 games). The BT HID driver covers both hardware revisions.

VID/PID: DS4 v1: 054C:05C4 (Sony, first-gen, shipped with PS4 launch units 2013–2016); DS4 v2: 054C:09CC (Sony, revised hardware 2016+, adds rumble/touchpad improvements). Both are covered by the same driver.

77-byte HID input report (report ID 0x11)

The DS4 BT report is significantly larger than the Xbox One BT 16-byte report. The extra bytes carry touchpad coordinates, gyroscope/accelerometer data, battery level, and extended button states.

Synthetic inject and snap/restore

• Synthetic inject: ds4_inject(report_77bytes) — injects a synthetic 77-byte report for the SRDX reverse channel or testing.
• Snap/restore: ds4_snap() / ds4_rest() — Mode-2 rollback state management.

21 checks PASS: VID/PID both revisions, each button individually, all 4 axes, triggers, touchpad click, PS button, hat switch all directions, battery level read, rollback restore. State at 0x9C0000. PASS: DS4 init=1 inj=1 rly=1.

ROM library CRC32 scanner (960b9bd — sigil-retropie)

A RetroPie is only as useful as its ROM library. tools/rom_scan.py is a host-side Python scanner (thin host tooling — same exception class as dpost.py) that walks /roms/<system>/ and identifies ROMs against official dat catalogs.

Two dat formats

• MAME dat (XML): arcade ROMs are ZIP files. The scanner CRC32s each file inside the ZIP and matches against the MAME dat's <rom> entries. This is the exact method MAME uses for ROM validation — a matched CRC32 against the dat means the ROM is byte-for-byte correct.
• No-Intro dats (XML): cartridge ROMs (SNES, NES, GBA, etc.) are single files. The scanner CRC32s the whole file and compares against the No-Intro dat's <rom crc="..."> attribute. No-Intro is the gold standard for console ROM preservation — a matched CRC means a verified, unmodified dump.
• Fallback title: if no dat is available or no CRC match is found, the scanner generates a title from the filename — strip region tags like (USA), (E), (J), replace underscores with spaces, title-case the result.

Output: lib/rom_catalog_gen.sg

A Sigil source file compiled into the sigilOS image — zero runtime file I/O needed to display the library. Functions:

The scanner also writes docs/rom_library.json — a human-readable JSON index for debugging and web display.

Two-level ROM browser (960b9bd — sigil-retropie)

ui/library_scene.sg + updated ui/launcher_app.sg deliver a two-level launcher: pick a system, then browse its ROMs in a card grid.

Level 0 — system browser (launcher_app.sg)

The existing system browser lists 73 systems in a scrollable list. Updated in this commit to wire EV_SELECT into Level 1: selecting a system opens its ROM library.

Level 1 — ROM browser (library_scene.sg)

A 4×5 card grid (4 columns, 5 rows = 20 ROMs per page, paginated). Each card shows the ROM title (from catalog or filename fallback), system name, and year.

• Info bar (bottom of grid): year, publisher, and a [dat verified] badge if rom_verified(i) is true — CRC32 matched against the official dat. The badge distinguishes exact dumps from filename-only matches.
• L1/R1 navigation: Left/Right shoulder buttons skip to the previous/next system that has ROMs — no empty system pages. lib_prev_system() / lib_next_system().
• EV_BACK: return to Level 0 (system browser).
• EV_SELECT: launch the selected ROM — calls launcher_launch(sys_id, rom_path).

API: lib_scene(sys, sel) (render the grid for system sys, selected index sel), lib_nav(ev) (handle input events), lib_next_system() / lib_prev_system().

BT gamepad stack — now three controllers

With the DS4 driver shipping, the sigilOS wireless gamepad stack covers the two dominant controllers. All three drivers implement the Mode-2 snap/restore ABI — any of them can serve as the SRDX netplay reverse channel.

The three drivers together cover the two dominant wireless controllers — Xbox One S and DualShock 4 together represent more than 80% of the installed wireless gamepad base. The USB generic driver covers wired controllers and the long tail of HID-compliant gamepads.