The Light Display Manager doesn’t start on Odroid XU4 on the recent mainline kernels with exynos_defconfig. I first noticed this problem during the Linux 4.8 rc testing and this problem persists in 4.9-rc1. I want to share the root-cause, and a work-around in this post. I’m running kernel 4.9.0-rc1 with exynos_defconfig on Ubuntu 16.04 with HDMI. Light Display Manager (lightdm) fails with the following errors.
Starting Light Display Manager...
[ OK ] Started Light Display Manager.
[ 15.538629] [drm:exynos_drm_framebuffer_init] *ERROR* Non-contiguous GEM mem.
[ 15.546149] [drm:exynos_drm_framebuffer_init] *ERROR* Non-contiguous GEM mem.
[ OK ] Stopped Light Display Manager.
This block repeats a few times until systemd gives up on starting lightdm. The system is operational with functioning serial console and networking, however the display doesn’t work. What Causes this problem? The following sequence of events is what leads to this problem The user space calls exynos_drm_gem_create_ioctl() with the EXYNOS_BO_NONCONTIG request to allocate GEM buffers. exynos_drm_gem_create() creates non-contiguous GEM buffers as requested. exynos_user_fb_create() comes along later and validates the GEM buffers to associate them to frame-buffer. The validation in check_fb_gem_memory_type() detects non-contiguous buffers […]
I recently installed Ubuntu 15.10 on Odroid-XU4 and set out to run the upstream kernel on it. After several trials and errors and being forced to reference various forums, I now have Odroid running the Linux 4.6 Kernel. In this article, I will share how to quickly get from unboxing to running the latest kernel with a short detour to upgrade to the Ubuntu 16.04 release. Without further ado, let’s get started. First of all, download the Ubuntu 15.10 image. You can find the release notes and self installing image here: Release notes for Ubuntu 15.10 (v1.0) ubuntu-15.10-mate-odroid-xu3-20160114.img.xz Prepare the microSD Card Once you’ve downloaded the image from the 2nd link above, follow the following steps to create a bootable microSD card with the image; I used a 32 GB Samsung microSD card. Insert the microSD card in its SD card adapter case in the SD card slot on your host PC or […]