Wacom digitizer starts to work after i2c_hid module restart only

Question

Wacom digitizer starts to work after i2c_hid module restart only

Closed this issue 4 years ago · 11 comments

Wacom pad ('keyboard') starts to work only if i2c_hid module was reloaded.

Answer 1 · 2019-07-09T13:28:10.000Z

So the keyboard will not work after booted up ?

Answer 2 · 2019-07-09T13:40:54.000Z

No, keyboard works. Keyboard area contains two pointing devices really: touchpad (Goodix chip) and Wacom digitizer. First is for fingers, second is for pen.

Answer 3 · 2019-07-09T14:14:32.000Z

So digitizer doesn't works after the boot , Right?

Answer 4 · 2019-07-09T14:15:04.000Z

Did you tried to look at the dmesg ?

Answer 5 · 2019-07-09T14:53:58.000Z

So digitizer doesn't works after the boot , Right?

yes.

Answer 6 · 2019-07-16T10:59:00.000Z

Did you tried to look at the dmesg ?

Yes, I look but didn't dig deeply. I think that source of problem is some ACPI method which switches touchpad or wacom digitizer on/off.

Answer 7 · 2019-07-16T11:11:59.000Z

I thing restart i2c_hid is re-initialize the hardware. Soon will take a look at the init command of the pad. Seems like it had a problem with sending byte. I had familiar with the i2c hardware. Timing must be at lease almost perfect to initialize the hardware. You should try adding some delay in us (Microsecond, at lease 100 us) before initialize the hardware ( wait for it to wake up from no power).

Answer 8 · 2019-07-16T14:52:07.000Z

I thing restart i2c_hid is re-initialize the hardware. Soon will take a look at the init command of the pad. Seems like it had a problem with sending byte. I had familiar with the i2c hardware. Timing must be at lease almost perfect to initialize the hardware. You should try adding some delay in us (Microsecond, at lease 100 us) before initialize the hardware ( wait for it to wake up from no power).

Yes but no. x86 world is a bit more complicated than ARM or bare hardware ;) Power management usually is delegated to the ACPI subsystem which has own scripts for switching modes of HW modules.

Answer 9 · 2019-07-16T15:06:52.000Z

So. It seems like the ACPI doesn't do the job well ?. The command is sent but wacom pad but no power to the wacom pad, right ?

Answer 10 · 2019-09-15T15:12:37.000Z

Forgot to mention about the startup durations of the device. ACPI stuff must send the power to the pad then wait to initialize (on the hardware level). Then send bytes to talk with the pad. Or easier way is to create custom run-at-boot scriptor some execbin that start and restart the service (such a stupid fun workaround xD ).

Answer 11 · 2020-12-25T22:24:43.000Z

Fixed in the LiveCD 5.10.2 by some magic with binding and unbinding devices at events from the WMI kernel driver.