Touchscreen does not work on Chromium OS

[Wouter G.]

So I recently installed Chromium OS on my laptop but the touchscreen isn't working and the touchpad gestures aren't working too. Is there anywhere I can download drivers for that?

[svprxme12]

On Thursday, May 4, 2017 at 4:32:31 PM UTC-7, Wouter wrote:

So I recently installed Chromium OS on my laptop but the touchscreen isn't working and the touchpad gestures aren't working too. Is there anywhere I can download drivers for that?

SAME HERE, I NEEEEEED HEEEELP

 

[Perry]

Same here

[Philipp Sponsel]

Same here!

[hcu...@chromium.org]

What laptop is it, and what touchscreen does it have? In general, drivers can't be downloaded individually for Chromium OS; they have to be built in to the installed image instead.

On Thursday, May 4, 2017 at 4:32:31 PM UTC-7, Wouter G. wrote:

[Philipp Sponsel]

On Thursday, February 14, 2019 at 7:52:07 PM UTC+1, hcu...@chromium.org wrote:
> What laptop is it, and what touchscreen does it have? In general, drivers be downloaded individually for Chromium OS; they have to be built in to the installed image instead.

Hi hcu,
Thanks for sharing this information, i‘m quite new to chrome os so this is a helpfull information.
Quoting your „they need to be build in to the installed image instead“ can you explain this a little bit more? Do i neee to compile the os by my own and implement the touch driver in this stage? Or is it easier e.g. Implementing files in the img file before porting it to my device?

And the next question: do you know if there is any source for chrome os drivers?

I would be happy to investigate but it seems you know more about this topic than me ;)

Best,
Phil

[Harry Cutts]

Hi Phil,

Chromium OS uses the drivers that are in the Linux kernel. You can find the source on Linus's GitHub, with the relevant drivers in drivers/hid. You might not need to write a driver, though.

Most touchscreen controllers use a protocol called HID, which the kernel already supports, but there are sometimes details that often need to be taken care of separately for a particular controller. So, there are two possibilities for why your laptop's touch screen isn't working:

1. the Linux kernel doesn't have a driver for the touch screen controller, or
2. the kernel has a driver, but it's outputting data that somehow doesn't work with the Chromium OS input stack (e.g. it could be missing a piece of information that the stack relies on).

To tell whether the kernel has a driver, you can open up the Chromium OS shell (called crosh) by pressing Ctrl+Alt+T, then enter the evtest command. That'll give you a list of the input devices that are connected to your laptop which the kernel recognises. If your touchscreen is one of them, it might be called something obvious like "Atmel maXTouch Touchscreen", or it might just be some part code. In any case, you can choose a device by number to print some information about it. Then try touching the screen and see if any events appear in the terminal. (They'll be after the "Testing ... (interrupt to exit)" line; here's a paste with some example output from a Chromebook.) If you get output corresponding to your touches from one of the devices in the list, then there's already a driver and we're looking at option 2. (Another option for this stage is to try installing a GNU/Linux distribution like Ubuntu to see if the touchscreen works on that.)

Otherwise, the kernel running on your machine doesn't have a driver for the touch screen. Depending on where you got your Chromium OS image, it may be that the relevant driver exists but wasn't included in the build (for speed and compactness reasons, normally). This is where knowing what touch controller is on your laptop is helpful, as then you can look in the drivers/hid/ directory in the kernel source. If there's one there, then you can build your own Chromium OS image to include it. The Chromium OS Developer's Guide describes how you can build an image, and the Kernel Configuration page is a good starting point for how to include the appropriate driver. Once you had that image, you would install it in the same way as the one you're currently running.

I would be surprised if there isn't a kernel driver for your touchscreen, but if there isn't then you'd need to do a bit of research into the controller, write up a driver and submit it to the kernel. I can point you to some resources for that if you get to that stage :-).

Hope this helps. Feel free to send me any other questions you have.

Harry Cutts

Chrome OS Touch/Input team

--
--
Chromium OS Discussion mailing list: chromium-...@chromium.org
View archives, change email options, or unsubscribe:
https://groups.google.com/a/chromium.org/group/chromium-os-discuss
---
You received this message because you are subscribed to a topic in the Google Groups "Chromium OS Discussion" group.
To unsubscribe from this topic, visit https://groups.google.com/a/chromium.org/d/topic/chromium-os-discuss/-QgUN0QcfS4/unsubscribe.
To unsubscribe from this group and all its topics, send an email to chromium-os-dis...@chromium.org.