Comment 8 for bug 1900254

The Elantech Touchscreen is not working in Lenovo Ideapad 5 15.

[ 0.550596] elants_i2c i2c-ELAN0001:00: i2c-ELAN0001:00 supply vcc33 not found, using dummy regulator
[ 0.551836] elants_i2c i2c-ELAN0001:00: i2c-ELAN0001:00 supply vccio not found, using dummy regulator
[ 0.560932] elants_i2c i2c-ELAN0001:00: elants_i2c_send failed (77 77 77 77): -121
[ 0.562427] elants_i2c i2c-ELAN0001:00: software reset failed: -121
[ 0.595925] elants_i2c i2c-ELAN0001:00: elants_i2c_send failed (77 77 77 77): -121
[ 0.597974] elants_i2c i2c-ELAN0001:00: software reset failed: -121
[ 0.621893] elants_i2c i2c-ELAN0001:00: elants_i2c_send failed (77 77 77 77): -121
[ 0.622504] elants_i2c i2c-ELAN0001:00: software reset failed: -121
[ 0.632650] elants_i2c i2c-ELAN0001:00: elants_i2c_send failed (4d 61 69 6e): -121
[ 0.634256] elants_i2c i2c-ELAN0001:00: boot failed: -121
[ 0.699212] elants_i2c i2c-ELAN0001:00: invalid 'hello' packet: 00 00 ff ff
[ 1.630506] elants_i2c i2c-ELAN0001:00: Failed to read fw id: -121
[ 1.645508] elants_i2c i2c-ELAN0001:00: unknown packet 00 00 ff ff

When booting a test Windows10 (sorry..), it works; so a HW fault can be excluded.
When using it, it produces errors:

[ 933.159820] elants_i2c i2c-ELAN0001:00: unknown packet 0e 00 04 03
[ 933.167034] elants_i2c i2c-ELAN0001:00: unknown packet 0e 00 04 03
[ 933.172617] elants_i2c i2c-ELAN0001:00: unknown packet 0e 00 04 13
[ 933.180073] elants_i2c i2c-ELAN0001:00: unknown packet 0e 00 04 03
[ 933.185652] elants_i2c i2c-ELAN0001:00: unknown packet 0e 00 04 13
[ 933.192860] elants_i2c i2c-ELAN0001:00: unknown packet 0e 00 04 03
[ 933.198440] elants_i2c i2c-ELAN0001:00: unknown packet 0e 00 04 13

and so on...

Same beheaviour for kernel 5.4.xx and 5.6.xx