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I'm trying to build a custom distro for a tablet, using the Yocto Project with the meta-intel layer. Everything builds OK and after flashing to the device, it boots but the screen goes blank when the i915 driver is initialised. Sometimes there are a couple of coloured lines across the screen, which looks to me like the device has crashed completely, though I can't be sure as there is only a USB port on it so I can't get a serial TTY to check it. If I add i915.nomodeset=1 to the command line, the system boots up fully, but doesn't initialise DRM, which I need. The kernel version I'm using is 3.19.5. I've managed to grab a picture of the logging output just before the screen goes off:

Boot Log

Does anyone know why this might be happening, and how to fix it?

Update

I managed to get a dump from dmesg with the screen off. You can see it here: dmesg dump

Andrew Porritt
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  • What does switching to text mode (Ctrl-Alt-F1 and so) produce? – Incnis Mrsi Sep 09 '15 at 16:19
  • Ctrl-Alt-F1, F2, F3, etc. don't seem to make any difference. I think the system is still running, as I can toggle numlock on the keyboard, so it can't have totally crashed. – Andrew Porritt Sep 09 '15 at 17:05
  • Can you start the system with something like `init=/bin/bash` as a kernel argument? – Incnis Mrsi Sep 09 '15 at 17:10
  • I can, and I could probably dmsg to a file, but I haven't got a way of accessing that file. In order to see the output, I can add i915.modeset=0 to the command line, but changing the command line requires reflashing the device, which would wipe the data. The device supposedly has a microSD socket, but I put a microSD in and it nearly got stuck. It didn't go quite all the way, but I didn't want to push it further in case it got totally stuck, and the device didn't register the card. It's a cheap Chinese tablet, so not sure if it's just a tight socket or not actually a microSD socket. – Andrew Porritt Sep 09 '15 at 18:12
  • Are you able to use a newer kernel? From what you've done it's clear the DRM driver isn't working properly, but this is updated very regularly. – teppic Oct 01 '15 at 17:34
  • Did it work booting with any other distro? http://askubuntu.com/questions/619872/installing-ubuntu-14-10-64-bit-on-a-windows-8-bay-trail-atom-tablet Did you try to change the BIOS for an opensource one? (Seabios or coreboot) – user152909 Oct 01 '15 at 17:20
  • We've given up on trying to build Linux for the device for now, as we have some tight time constraints for the project, so we're just using the version of Android available for the tablet instead. I may revisit trying to get Linux running if I get a chance later. Thanks for the suggestions. – Andrew Porritt Oct 08 '15 at 11:51

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