[Blitzedzz-3]

Summary

Adds support for the Redragon M901 Perdition (04d9:fc5e), the M901-K-2 "Perdition4" variant — a wired Holtek mouse that runs the same RDCfg OEM firmware family and settings memory layout as the Redragon M612/M724.

• New REDRAGON_M901_MODEL descriptor (src/redragon/m901.ts) reuses the shared Holtek transport and the 0xCFF DPI table.
• RedragonModel.replyAddressBase covers the one wire difference found: this firmware answers a read with byte 3 = 0x60 + addressHigh, where the M612/M724 answer 0x32 + addressHigh.
• buttons and lighting are now optional in the model descriptor. The M901 model leaves both unset because the physical side-button order and effect names are not verified on this unit, so the status omits the button editor and lighting card instead of writing guesses.
• The existing Redragon registry entry serves 0xfc5e too.

Hardware verification

Tested on a real unit over hidraw (interface 2, 0xFFA0:0x01, feature report 2):

• Full 0x0000-0x07ff settings dump: captures/redragon-m901/memory-dump.hex.
• readStatus: 5 profiles, DPI stages 500 / 1000 / 2000 / 3000 / 6200, active profile 2.
• Idempotent polling write and a DPI round trip (1000 -> 800 -> 1000) both read back; the settings memory was byte-identical to the dump afterwards.

Public references for the device and protocol:

• dokutan/mouse_m908 lists 0x04d9:0xfc5e as M901-K-2 "Perdition4" with generic support.
• ernesto-elsaesser/usb-mouse-config documents the same F2/F3/F5 framing, the 0x42/0x102/0x1b2/0x262/0x312 DPI blocks, the 20-slot keymap addresses and the 0xCFF DPI code table.

Details: docs/redragon-m901-testing.md.

Checks

• npm run check (build + full test suite + pack dry run) passes: 3049 tests, 0 failed.
• New tests: src/drivers/redragon/m901.test.ts (dispatch, read status, reply header, DPI codec, bracketed polling write, and the deliberate button/lighting omission).

Note

Add Redragon M901 Perdition (04d9:fc5e) support to Redragon driver

• Adds the M901 model descriptor with wired transport, 5 DPI stages up to 12400 DPI, and its own read-reply address base in m901.ts; registers it in the Redragon catalogs in index.ts
• Extends RedragonModel in holtek.ts with optional button, lighting, and reply-address base fields, and lets redragonDecodeRead validate non-default reply headers
• M901 button and lighting layouts are unverified, so readStatus omits those fields and setButtonMapping/setLighting throw model-specific errors for the M901 in hid.ts
• Includes a captured memory dump, hardware testing notes in redragon-m901-testing.md, and full client tests against a simulated M901 device in m901.test.ts
• Behavioral Change: RedragonModel button/lighting fields are now optional; models without them return status without button or lighting data

^{Macroscope summarized 069f9dc.}

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• Source mode: Auto
• Repository: OpenMouse-Project/mouse-protocol
• Branch: main
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• Commit: b62a1cc
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Commits

Reviewing files that changed from the base of the PR and between b62a1cc and 069f9dc.

Files selected for processing: 8

• captures/redragon-m901/memory-dump.hex
• docs/redragon-m901-testing.md
• src/drivers/redragon/hid.ts
• src/drivers/redragon/m901.test.ts
• src/drivers/registry.ts
• src/redragon/holtek.ts
• src/redragon/index.ts
• src/redragon/m901.ts

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[macroscopeapp]

Approvability

Verdict: Approved at 069f9dc

Macroscope's review found this PR approvable — Adds M901 support for DPI, polling and profiles using the existing Holtek driver, backed by captured hardware data and round-trip evidence. Unverified button and lighting controls remain disabled, while existing models retain their protocol defaults.

Notes:

• Your repo's Minimum Blocking Severity is Off, so correctness findings do not automatically block approval.

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