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Software controllable USB ports already are a thing, Per-port power switching can be found in the USB 2.0 spec and there's a bunch of hubs out there that implem
by Goz3rr 3y ago
Software controllable USB ports already are a thing, Per-port power switching can be found in the USB 2.0 spec and there's a bunch of hubs out there that implement it, controllable via USB instead of I2C. Since USB 3.2 any device that has downstream type C ports is required to implement PPPS.
A DIY hub that uses a chip with PPPS support can be found here for example: https://oshwlab.com/iamseer/ch335-hub https://oshwlab.com/iamseer/ch335-hub
- boffinAudio 3y agoCool, got any suggestions for products that already implement this, particularly those with existing software shims that could be easily integrated into a test suite? I'd be a happy customer if there were such a thing, easily orderable, but I confess I don't quite know what keywords to use to find it ..
- seba_dos1 3y ago"already"? It's something available since USB 1.0 has been created (see section 11.10). For example, it can be automatically used by the Linux kernel (after setting pm_qos_no_power_off to 0), and recently a node to disable a port explicitly has been added as well. The support for commands themselves (SET/CLEAR_FEATURE) is mandated by the spec, so all hubs support it. However, some hubs don't feature port power control at all (are physically unable to selectively turn off power - you can only turn them all off or not at all), but for those it doesn't matter how you control them ;)