Mesa hm2/hm2_7i96s.0: error finishing read

I also tried linux-image-5.2.0-1-rt-amd64 and get the spikes there too.

I built my own "linux-image-5.0.21-rt16" and here I don't get the latency spikes. (The larger spike in the image was from dragging the browser window around; it still wasn't enough to trigger any latency errors from linuxcnc.)


I guess next step is to try a 5.2 kernel built on the same config. But not today! *snooze*

An interesting result here comparing Debian's linux-image-5.2.0-1-rt-amd64 and my home-built linux-image-5.2.21-rt15:

Debian linux-image-5.2.0-1-rt-amd64:


DIY linux-image-5.2.21-rt15:


So the issue might have something to do with Debian's patches or the kernel config rather than the kernel version.

All my tests have been with home built images, and I have never seen the really bad latency
issues on these kernels (regardless or version) that the debian kernels show.

I do find the 4.19 kernel in general is much better latency wise than later kernels,
and may be needed on some host hardware.

That should explain the difference between your 8300 and bensttech's then?

What sources do you use for your home built images? I'm using the kernel stable repo (and apply the PREEMPT_RT patches according to the instructions ).

Yes, I just use the kernel.org sources and RT patches and build with a script like:

mkdir rtlinux
cd rtlinux
wget www.kernel.org/pub/linux/kernel/v5.x/linux-5.10.145.tar.xz
wget www.kernel.org/pub/linux/kernel/projects...10.145-rt74.patch.gz
tar -xpf linux-5.10.145.tar.xz
gunzip patch-5.10.145-rt74.patch.gz
cp patch-5.10.145-rt74.patch linux-5.10.145
cd linux-5.10.145
cat patch-5.10.145-rt74.patch | patch -p1
make xconfig
make -j4
sudo make INSTALL_MOD_STRIP=1 modules_install
sudo make install

Usually the only thing I change (if needed) in xconfig is the preemption mode.