Touchscreen does not always start

I have a Raspberry Pi with a touchscreen, and HiFi Berry Amp 2, as well as a couple of encoders, buttons. It is powered by a 12V 3A power supply to the Amp 2.

When I start the system the touchscreen does not always come on. Particularly first thing in the day, from cold. (If it is off for a while). The issue is solved by simply restarting - then it nearly always works. Also usually if only powered down for 1/2 an hour or so.

Is there a command to start/restart the touchscreen process that I could try mapping to a button action? Or other options to try like changing the order of the boot processes?
I do not think it is possible to start the touchscreen via SSH (?)

Volumio Information

Volumio Version: 2.873
Hardware: Raspberry Pi 4
DAC: HiFi Berry Amp 2

If you are using the Touch Display plugin the easiest would probably to disable and re-enable the plugin from the UI using a browser on another device (e.g. smartphone).

Does the display work during the boot process?

No, the display does not come up at all during the boot process, stays black.

After rebooting, when it does work, you can see the screen brightening early in the boot process even before text appears on the screen.

To me it seems to be a hardware issue with the display then. So restarting the touch display plugin will most probably not help.

Thanks for the suggestions - I will try that anyway when I get a chance - tomorrow. (It currently switches on every time … this only seems to happen when the device has been off for quite some time).

Follow-up: Restarting the display plugin did indeed not work.
Comparing Xorg.log between no touchscreen and successful boot, there is a difference:
FBTURBO(0): Virtual size is 640x480 (pitch 640) vs
FBTURBO(0): Virtual size is 800x480 (pitch 800)
Then later in the successful boot version there are lines relating to the input device (touchscreen)

So it looks like the touchscreen is not detected during boot. In Raspberry Pi forums there are posts about possible power issue. (Though when the device successfully boots, I do not see any other power issues)

I’ll try adding boot delay or adding a separate power input for the touchscreen.

Thanks for reporting your findings.

A too weak power supply might be the reason for the start issue. Let’s hope it isn’t a bad solder joint or capacitor.