Dell Latitude 5400 Chrome (google/sarien): GNU/Linux: Touchscreen does not work

[paulmenzel]

Installing RW_LEGACY (TianoCore) using the Chrome OS Firmware Utility script worked fine.

In Ubuntu 21.10 and Debian sid/unstable, the touchscreen is not working. Linux reports:

[    0.000000] microcode: microcode updated early to revision 0xea, date = 2021-01-05
[    0.000000] Linux version 5.13.0-19-generic (buildd@lgw01-amd64-013) (gcc (Ubuntu 11.2.0-7ubuntu2) 11.2.0, GNU ld (GNU Binutils for Ubuntu) 2.37) #19-Ubuntu SMP Thu Oct 7 21:58:00 UTC 2021 (Ubuntu 5.13.0-19.19-generic 5.13.14)
[…]
[    0.000000] DMI: Dell Inc. Sarien/Sarien, BIOS Google_Sarien.12200.155.0 07/29/2020
[…]
[    9.352368] i2c_designware i2c_designware.0: controller timed out
[    9.352386] mip4_ts i2c-MLFS0000:00: nothing at this address