colejhudson/graphics-issues-log.md

## graphics-issues-log.md

      
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              graphics-issues-log.md
            
          
    The Problem

Started having issues on Ubuntu with the HDMI output. I hit the power
button with my foot and caused the computer to restart. After, the screen was
blank, save for its default message indicating to 'Check the video cable' I
had tried switching the display, restarting, a different HDMI cabel, etc. I have a
Gigabyte motherboard, an intel CPU, an AMD graphics card is installed, but
has been broken for quite some while.
Log

uname -a
# Linux dev 4.4.0-101-generic #124-Ubuntu SMP Fri Nov 10 18:29:59 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

Via Stack Overflow I found that you can switch between graphics driver, hence
sudo prime-select intel
# Info: the current GL alternatives in use are: ['mesa', 'nvidia-390']
# Info: the current EGL alternatives in use are: ['mesa-egl', 'nvidia-390']
# Info: selecting nvidia-390-prime for the intel profile
# update-alternatives: using /usr/lib/nvidia-390-prime/ld.so.conf to provide /etc/ld.so.conf.d/x86_64-linux-gnu_GL.conf (x86_64-linux- gnu_gl_conf) in manual mode
# update-alternatives: using /usr/lib/nvidia-390-prime/ld.so.conf to provide /etc/ld.so.conf.d/x86_64-linux-gnu_EGL.conf (x86_64-linux-gnu_egl_conf) in manual mode
# update-alternatives: using /usr/lib/nvidia-390-prime/alt_ld.so.conf to provide /etc/ld.so.conf.d/i386-linux-gnu_GL.conf (i386-linux-gnu_gl_conf) in manual mode
# update-alternatives: using /usr/lib/nvidia-390-prime/alt_ld.so.conf to provide /etc/ld.so.conf.d/i386-linux-gnu_EGL.conf (i386-linux-gnu_egl_conf) in manual mode

xrandr and wmctrl both output Cannot open display.
Listing the hardware interfaces, specifically for video devices, yields:
sudo lshw -C display
 # *-display UNCLAIMED     
 #      description: VGA compatible controller
 #      product: Advanced Micro Devices, Inc. [AMD/ATI]
 #      vendor: Advanced Micro Devices, Inc. [AMD/ATI]
 #      physical id: 0
 #      bus info: pci@0000:01:00.0
 #      version: c7
 #      width: 64 bits
 #      clock: 33MHz
 #      capabilities: pm pciexpress msi vga_controller bus_master cap_list
 #      configuration: latency=0
 #      resources: memory:c0000000-cfffffff memory:d0000000-d01fffff ioport:e000(size=256) memory:dfe00000-dfe3ffff memory:dfe40000-dfe5ffff

Checking whether lightdm is running via service indicates
that it is. Curiouslly checking /tmp yields no unix domain
socket for X11 IPC. So far as I understand lightdm requires,
and manages itself, X11. Upon further inspection this doesn't
seem to be the case.
The Solution

Next I googled 'disable graphics card ubuntu command line' having
run sudo lshw -c video again and noticing the it was listing
'Advanced Micro Devices, Inc.' as the product. Given that my GPU
is an AMD, and that it's broken. I searched for a means to disable
the GPUI such that the onboard graphics on my CPU is used by default.
Hence I found this Stack Overflow post which suggests you edit /etc/default/grub as such:
Add radeon.modeset=0 to this line -> GRUB_CMDLINE_LINUX_DEFAULT="quiet splash""
so that it reads -> GRUB_CMDLINE_LINUX_DEFAULT="quiet splash radeon.modeset=0"

Subsequently, running sudo update-grub updates the GRUB config and rebooting
the system via sudo reboot caused the restarted computer to use the onboard
graphics by default and fixing everything!