pi touchscreen stopped working

[nebogeo]

Hi all,

I have two official pi touchscreens, and they have both stopped working one after the other (a week or so between them) with the same symptoms (just flash on reboot, then black). I'm running them on external power with the ribbon cable. I've tried different cables but I don't think they are the problem as the screen is detected ok:

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dmesg | grep -i ft5406
[    6.568213] rpi-ft5406 rpi_ft5406: Probing device
[    6.568761] input: FT5406 memory based driver as /devices/virtual/input/input2

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cat /proc/cmdline | grep bcm2708_fb
dma.dmachans=0x7f35 bcm2708_fb.fbwidth=800 bcm2708_fb.fbheight=480 bcm2709.boardrev=0xa01041 bcm2709.serial=0x3fec997e smsc95xx.macaddr=B8:27:EB:EC:99:7E bcm2708_fb.fbswap=1 bcm2709.uart_clock=48000000 bcm2709.disk_led_gpio=47 bcm2709.disk_led_active_low=0 vc_mem.mem_base=0x3dc00000 vc_mem.mem_size=0x3f000000  dwc_otg.lpm_enable=0 console=ttyAMA0,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait

I tried resetting my config via

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sudo apt-get update
sudo apt-get install --reinstall libraspberrypi0 libraspberrypi-{bin,dev,doc} raspberrypi-bootloader
sudo reboot

I upgraded everything else and added

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device_tree=

to config.txt... I don't think I updated anything suspicious at the time they stopped working (I was running some I2c sensors tho), so I'd expect hardware failure, but both at roughly the same time?

cheers,

dave

[nebogeo]

I forgot to say that this is on a Pi 2B board.
I just tested this on a different board of the same type and get the same problem. Perhaps I blew both of them up?

[DougieLawson]

I'd start with a factory fresh 8GB SDCard and a fresh download of NOOBS 2.0 or Raspbian Jessie 2016-09-27

That should eliminate any possible software screw up. If they both don't work with that assume a hardware fault (although it's exceedingly unlikely that both would fail like that).

[6by9]

Why are you trying to disable device tree? That's probably your problem, although I do also have a recollection that as device tree is required for the 4.4 tree to boot properly so they've disabled part of that option.

If you've added "i2c_vc=on" that would also kill the touchscreen.

[nebogeo]

Just to follow up, it looks like both the screens are indeed dead.
We bought some more for another project and they work fine.

The dead ones are still appearing via dmesg etc but with no visible screen activity other than a quick flash at boot. I was running two DS18B20 temperature sensors at the time, actually via one wire protocol with:

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dtoverlay=w1-gpio

Odd if this caused these problems as the screens seem alive internally still...

[6by9]

Did you double check the cable from the controller board to the display? Dmesg will report that it found the controller, but there's no way of telling if the display itself is connected to the output side of the controller.

[nebogeo]

OK red face here - after some months, a new Pi 3 board and new cable (but same sdcard) these touchscreens are mysteriously back to life... One of the old Pi 2s still doesn't work with them - but I the other one I was testing it with before is fine.

Searching for the user error, I think it must be a power problem on that one board - as the device is found but the backlight is off.