On Mon, May 10, 2021 at 10:15:14AM +0200, Johan Hovold wrote: > On Thu, May 06, 2021 at 01:44:52PM +0100, Sean Young wrote: > > This is a new rc-core driver for the USB-UIRT which you can see here > > http://www.usbuirt.com/ > > > > This device is supported in lirc, via the usb serial kernel driver. This > > driver is both for rc-core, which means it can use kernel/BPF decoding > > ec. Also this implement is superior because it can: > > - support learning mode > > - setting transmit carrier > > - larger transmits using streaming tx command > > This looks like something which should have been implemented as a > line-discipline or serdev driver instead of reimplementing a minimal > on-off ftdi driver and tying it closely to the RC subsystem. The device is an infrared device, I'm not sure what it is lost by doing it this way. The "minimal on-off ftdi driver" is super trivial. > Why can't you just add support for the above features to whatever > subsystem is managing this device today? > > Serdev still doesn't support hotplugging unfortunately so that route may > take a bit more work. There seems to be at least three ways of attaching drivers to serial devices: serio, serdev, and line-discipline. All seem to have limitations, as you say none of them provide a way of hotplugging devices without user-space attaching them through an ioctl or so. If you want to go down this route, then ideally you'd want a quirk on fdti saying "attach usb-uirt serdev device to this pid/vid". Considering module dependencies, I don't know how that could work without again userspace getting involved. Getting userspace involved seem like a big song and dance because the device uses an fdti device, even though it's not a serial port because it's hardwired for infrared functions, no db9 connector in sight. Sean
