Graham,
Please follow the steps in comment #2. Please also tell us if using an older kernel fixes the problem for you like Peter says. Older kernels can be found here:
https://kernel.ubuntu.com/~kernel-ppa/mainline/?C=N;O=D
If no older kernel fixes the problem then that means Peter needs to open a separate bug.
Graham,
Please follow the steps in comment #2. Please also tell us if using an older kernel fixes the problem for you like Peter says. Older kernels can be found here:
https:/ /kernel. ubuntu. com/~kernel- ppa/mainline/ ?C=N;O= D
If no older kernel fixes the problem then that means Peter needs to open a separate bug.