Linux 5.2 Should Resolve Many AMD Ryzen Laptop Touchscreens/Touchpads Not Working
A number of AMD Ryzen laptops up to this point haven't had working touchscreens/touchpads when running on the mainline kernel. That's been due to a lack of AMD PCIe MP2 I2C controller support, but a new driver is being merged for Linux 5.2 to properly support that controller.
The i2c-amd-mp2 driver is currently queued in i2c-next for introduction with the Linux 5.2 merge window, which should open tomorrow assuming Linux 5.1 releases as expected.
This long overdue driver is based on code AMD released back in 2018 but took a rewrite and going through several rounds of review to get it into shape for merging to mainline. But now it's queued and ready for use with Linux 5.2 mainline.
If your touchpad is currently working on an AMD Zen notebook, it's possible the original AMD MP2 driver is at play. Ubuntu has been one of the distributions carrying a patch of AMD's original driver code. Now once upgrading to Linux 5.2+, the support should be even better thanks to various functionality improvements over the original driver patched into Ubuntu kernels. Other AMD laptop owners have resorted to using a DKMS version of this driver in order to make use of their laptops.
Among the many laptops this new AMD MP2 driver should help for working touchpads or touchscreens are the Dell Latitude 5495, Lenovo Yoga 530, Lenovo Ideapad 530s, Acer Nitro 5, Huawei Matebook D, and many others sporting this new controller.