On 8/18/20 4:34 PM, Jason Wessel wrote:
After the initial configuration some USB keyboard+mouse devices never return any kind of event on the interrupt line. In particular, the device identified by "Cypress Cypress USB Keyboard / PS2 Mouse as 3f980000.usb/usb1/1-1/1-1.3/1-1.3:1.0/0003:04B4:0101.0001/input/input0" never returns a data packet until the first external input event.
I found this was also true with some newer model Dell keyboards.
When the device is plugged into a xhci controller there is also no point in waiting 5 seconds for a device that is never going to present data, so the call to the interrupt service was changed to a nonblocking operation for the controllers that support this.
With the patch applied, the rpi3 and rpi4 work well with the more complex keyboard devices.
Please extend the comment in the code, it is not clear from it or from the commit message what the problem really is that this patch tries to fix.
Also, the printf() below the return 1 is never reached.