I love my System76 Galago Pro. I’ve had it since last summer, and it has been a great portable workstation. I must admit, however, that it isn’t perfect. The whole time that I’ve been using this laptop, it’s fan has been hyperactive. It would spin up for seemingly any reason, and the machine would heat up extremely quickly. I was willing to live with these problems, but they were irksome.
Another, seemingly related problem, was that most video suffered from extreme screen tearing. It was physically painful to be watching a YouTube video and have it visually rip itself in half every few seconds.
This weekend, I finally got fed up with it. I decided to try to fix the tearing problem. I knew that my computer has a Kaby Lake Intel i7 processor and an Intel HD 620 integrated graphics card. Armed with that knowledge, I hit the search engines.
It didn’t take long to find this helpful article on ArchWiki about how to try out the Tear-Free setting for the Intel Xorg graphics driver. The Arch page suggests adding a line to your
/etc/X11/xorg.conf.d/20-intel.conf. Unfortunately, I didn’t have that file. In fact, the
/etc/X11/xorg.conf.d/ directory didn’t even exist on my system. By searching the entire filesystem for
xorg.conf, I was able to locate the example configuration file shipped by the Intel Xorg driver at
README file in that directory indicated that I should see
man intel for information about the different settings for the driver.
man 4 intel and found the documentation for the TearFree option:
Option "TearFree" "boolean" Disable or enable TearFree updates. This option forces X to perform all rendering to a backbuffer prior to updating the actual display. It requires an extra memory allocation the same size as a frame‐ buffer, the occasional extra copy, and requires Damage tracking. Thus enabling TearFree requires more memory and is slower (reduced throughput) and introduces a small amount of output latency, but it should not impact input latency. However, the update to the screen is then performed synchronously with the vertical refresh of the display so that the entire update is completed before the display starts its refresh. That is only one frame is ever visible, preventing an unsightly tear between two visible and differing frames. Note that this replicates what the compositing manager should be doing, however TearFree will redirect the compositor updates (and those of fullscreen games) directly on to the scanout thus incurring no additional overhead in the composited case. Also note that not all com‐ positing managers prevent tearing, and if the outputs are rotated, there will still be tearing without TearFree enabled. Default: TearFree is disabled.
Given how badly my graphics were performing, I figured it was worth the tradeoff. I created
xorg.conf.d and copied the example configuration file into it. Then I added the TearFree option so that the file looks like this:
# /etc/X11/xorg.conf.d/20-intel.conf Section "Device" Identifier "Intel" Driver "intel" Option "TearFree" "true" EndSection
I restarted with this config and the difference was striking. I can watch streamed HD videos without tearing and without my computer heating up significantly. In order to get a good frame rate consistently, I do need to run at 1920×1080 instead of 3200×1800, but I can live with that.
After digging through the Xorg logs, I’ve come to the conclusion that all of my graphics up to this point were software rendering, hence the heat and fan noise. I can’t believe that I’ve been living with software rendering for months, but I have the log files to prove it.
As a simple test for whether you are running Xorg with hardware acceleration (if you have an Intel graphics chip), you can search your Xorg log for the keyword “intel”. Something like this should work:
grep "intel" /var/log/Xorg.0.log # the log may also be at ~/.local/share/xorg/Xorg.0.log
If you see no lines about configuring the Intel input driver, you’re not using your integrated graphics card either.