https://forge.codesys.com/forge/talk/Runtime/thread/b743acd533/2023-12-25T08:46:02.324000ZRecent posts to Raspberry pi rt preempt2023-12-25T08:46:02.324000Z2023-12-25T08:46:02.324000Zoe2swmhttps://forge.codesys.com/u/oe2swm/https://forge.codesys.comc9a614115c1a918e09b5aa41d91efef620b29431

<div class="markdown_content"><p>Hello,</p> <p>I tried very hard to get Raspberry working with RT PREEMPT Kernel,<br/> But still i cannot get it working. Is there someone who can provide a Image for Raspberry 3b or 4(4gb)</p> <p>Thanks a lot!</p></div>

2022-04-19T11:47:19.682000Z2022-04-19T11:47:19.682000Zmondinmrhttps://forge.codesys.com/u/mondinmr/https://forge.codesys.com9257826d2146b055046b0e8b66d0a4114287e649

<div class="markdown_content"><p>I searched again!</p> <p>RPI 2 is supported in debian with<br/> linux-image-rt-armmp in 32 bits arch</p> <p>RPI 3 i cannot find info</p> <p>RPI 4 apparently only in 64 bits linux-image-rt-arm64 (Tested by me in debian daily build) and CODESYS for arm at 64 bits</p></div>

2022-04-19T10:26:50.357000Z2022-04-19T10:26:50.357000Zmondinmrhttps://forge.codesys.com/u/mondinmr/https://forge.codesys.com1c3960c98084d9c0b639b8765b7681355d45ebc5

<div class="markdown_content"><p>I just mounted a PI2 image:</p> <div class="codehilite"><pre><span></span><span class="err">$</span> <span class="err">unxz</span> <span class="err">20220121_raspi_2_bullseye.img.xz</span> <span class="err">$</span> <span class="err">sudo</span> <span class="err">losetup</span> <span class="err">-Pf</span> <span class="err">20220121_raspi_2_bullseye.img</span> <span class="err">$</span> <span class="err">sudo</span> <span class="err">mount</span> <span class="err">/dev/loop24p2</span> <span class="err">/mnt</span> <span class="err">$</span> <span class="err">cd</span> <span class="err">/mnt/etc/apt</span> <span class="err">$</span> <span class="err">cat</span> <span class="err">sources.list</span> <span class="k">deb</span> <span class="s">http://deb.debian.org/debian</span> <span class="kp">bullseye</span> <span class="kp">main</span> <span class="kp">contrib</span> <span class="kp">non-free</span> <span class="k">deb</span> <span class="s">http://security.debian.org/debian-security</span> <span class="kp">bullseye-security</span> <span class="kp">main</span> <span class="kp">contrib</span> <span class="kp">non-free</span> <span class="c"># Backports are _not_ enabled by default.</span> <span class="c"># Enable them by uncommenting the following line:</span> <span class="c"># deb http://deb.debian.org/debian bullseye-backports main contrib non-free</span> </pre></div> <p>Enable those repo in raspbian than:</p> <div class="codehilite"><pre><span></span>$ sudo apt-get update $ sudo apt-get install linux-image-rt </pre></div> <p>NEVER DO apt-get upgrade!!!!<br/> Remove repos before!!!</p> <p>In a Raspberry PI 4 64bit it worked for me, but now I'm switching to a my distro built with YOCTO.</p></div>

2022-04-18T17:40:56.892000Z2022-04-18T17:40:56.892000Zhcvoorthttps://forge.codesys.com/u/hcvoort/https://forge.codesys.com61eab48a0980fcc895d118d0d334487b9a1fe4eb

<div class="markdown_content"><p>Thanks. I went through it but only saw standard builds (tested). Could you point me to the precompiled images with preempt-rt patch?</p></div>

2022-04-18T17:34:02.899000Z2022-04-18T17:34:02.899000Zmondinmrhttps://forge.codesys.com/u/mondinmr/https://forge.codesys.comadd57a4421be8056dc4a9e03e741271a648e6b2d

<div class="markdown_content"><p><a href="https://wiki.debian.org/RaspberryPi4" rel="nofollow">https://wiki.debian.org/RaspberryPi4</a></p></div>

2022-04-18T17:31:15.632000Z2022-04-18T17:31:15.632000Zhcvoorthttps://forge.codesys.com/u/hcvoort/https://forge.codesys.come99f78351fb1a0e97539d4e21095aca8435696b9

<div class="markdown_content"><p>Thanks for your comment. Do you have link for the debian repo?</p></div>

2022-04-18T17:24:32.644000Z2022-04-18T17:24:32.644000Zmondinmrhttps://forge.codesys.com/u/mondinmr/https://forge.codesys.combbad8a4fa80af1e40074b3e9d6e70d5b913166fe

<div class="markdown_content"><p>You could use Debian image.<br/> In Debian repo you can find RT PREEMPT precompiled path.<br/> Tuning kernel cmdline using CPU pinning and using a fixed pinning on codesys task make possible a jitter &lt;30us on a PI4.</p></div>

2022-04-18T08:38:42.589000Z2022-04-18T08:38:42.589000Zhcvoorthttps://forge.codesys.com/u/hcvoort/https://forge.codesys.comf7e572e95aa8808efa6e35fab3164b29578203cc

<div class="markdown_content"><p>Hi,</p> <p>A couple of years ago I used the Pi as a soft PLC in which you could apply an rt-preempt patch to the kernel to reduce jitter. I remember that Edwin also made a short post on how to do this. Is there still a quick way to patch a kernel for a Raspi 3B? Or do I really have to build a kernel?</p> <p>Thanks!</p> <p>Carsten</p></div>