Wellspring Emulation

[1Revenger1]

Adds Wellspring Trackpad emulation for older macOS versions, allowing multitouch support down to 10.5. The original implementation is used for Sierra and newer, as it is easier to use AppleMultitouchDevice rather than trying to work around Sandbox restrictions in newer macOS versions like Ventura.

I have not had a chance yet to test in older macOS versions, though will test on my M4700 with an Alps trackpad when I get the chance.

This is still a heavy WIP, am mainly opening this to track changes for now. This does currently work in Catalina.

[usr-sse2]

In which MacBook is Wellspring trackpad found? Is it used in modern models or it can become unsupported in the next macOS release?

[1Revenger1]

These trackpads are still used in the force touch macbooks. It's the same packet layout over SPI, though they use a Report ID of 0x75 instead of 0x74. There is some added fields for the newer trackpads, but MultitouchSupport.plugin checks the length before reading these added fields.

[1Revenger1]

These would need to be uncommented to add pressure support, and may need to change the product ID/other device properties. As long as we give the correct sizes in the header though, older versions should still parse this fine.

[1Revenger1]

These trackpads are still used in the force touch macbooks. It's the same packet layout over SPI, though they use a Report ID of 0x75 instead of 0x74. There is some added fields for the newer trackpads, but MultitouchSupport.plugin checks the length before reading these added fields.

So it turns out there is a different header for the newer trackpads, but that shouldn't be too bad to handle. The finger data is the same, so that logic can be shared if needed. Ventura still supports the reports for the USB trackpads too (OCLP just reinjects AppleUSBMultitouch and doesn't touch MultitouchSupport.plugin which does the actual decoding of packets.)

I don't think they'll remove support for the older trackpads, but I'll look into what's needed to support newer trackpads. It's likely adding properties for actuator/force touch, changing product ID, sensor Params/region Params, and changing the header.

[1Revenger1]

This is slightly broken in Ventura (if anyone ends up trying). AppleUSBMultitouch was removed, so that dependency needs to be removed for the EventDriver. Should be an easy fix though.

Ventura works now. I'm not really sure how I feel about the workaround though. Sandbox is preventing anything other than AppleUSBMultitouch, AppleMultitouchDriver, and some other drivers from being opened by WindowServer. It does allow anything with the IOHID prefix though.