Ubuntu/Debian and Broadcom BCM5762

I picked up an HP EliteDesk 705 G3 Mini PC as the potential third node for a Proxmox cluster. While I wouldn’t be using HA, I did not want to cause potential problems with a tied quorum vote. For under CDN$100 I got an AMD Pro A10-8770E, 8GB RAM and a 128GB (Samsung OEM) SSD. It is really small and uses next to no power. And, it has no noisy fans.

While the jury is still out on this approach because the DL360 G8’s fans are so annoying, I still installed Proxmox on the 705. Part of this was because I wanted to experiment with only having one NIC and using VLANs. Setting up the VLANs was no real issue – just a little more fooling around on the command line manually configuring the admin interface to work on a VLAN and allow the other VLAN bridges to be available. However, this really messed with my head as I would have the network interfaces drop offline when under heavy load. And sometimes for what seemed to be no reason at all! Of course, since this was my first time using a single NIC, I was placing the blame on me not setting up the VLANs correctly.

Maybe the issue was Proxmox (and Debian?). So, I put on Ubuntu 22.04 server and desktop as well as Linux Mint 21 to test that theory out. No VLANs, just a “normal” installation. Same issue: under load the NIC would go offline and the console (for server) would sow my field with salt – or rather a bunch of errors. Since this occurred with and without VLANs, the error had to be with something other than my VLAN configuration.

After much digging, there seems to be a (longterm?) nasty kernel bug with tg3 and the Broadcom BCM5762 NIC.

The solution that worked for me was to add iommu=pt to /etc/default/grub:


The just run update-grub and reboot. Problem fixed.

I read other suggestions on blacklisting tg3 in /etc/modprobe.d as that was the issue but that did not work for me.

About Mike Pelley

Let’s see… A little about me… I’ve been around information technology since 1983 with computers such as DEC Rainbows (weird machine – the standard DOS couldn’t format its own floppy disks – remember them? – and I had to format them on a friend’s IBM PC) to Radio Shack TRS-80 to Apple ][e and Apple //c in the beginning. I have programmed in 8-bit assembly language on 6502, FORTRAN and COBOL on IBM System/370 (and I still hate JCL), VAX BASIC and COBOL (and a weird and massive WordPerfect 4.0 macro) on DEC VMS (Alpha), C/C++ on Digital Unix (ALPHA), and C/C++, Perl (it may be powerful but I still hate it), PHP on Linux (Red Hat, Centos, Ubuntu, etc.). I have work with databases such as Digital RDB (later to become Oracle RDB), Oracle DBMS, Microsoft SQL Server, MySQL and PostgreSQL on VAX, Alpha, Sun and Intel. Check out my professional profile and connect with me on LinkedIn. See http://lnkd.in/nhTRZe I still think that Digital created some of the best ideas in the world: VAX clustering, DSSI disks (forerunner to SCSI) and the Alpha processor (first commercial 64-bit processor – Red Hat screamed on an Alpha!). DEC just could not seem to be able to give air conditioners away to someone lost in the Sahara Desert! VMware is one of the best ways to get the most out of an x64 server. And I have tried Oracle VM, Virtual Box and Microsoft Virtual Server. Outside of that I am a huge military history buff starting in the early 20th century. I love Ford Mustangs (my ’87 Mustang GT was awesome) and if I had the money I would have a Porsche 928S4. If I had a lot of money I would have a Porsche 911 Turbo. I also play too much AmrA 3 Exile mod. Over 5,000+ hours... I have a wonderful son, Cameron. I have a long suffering (Do you really need all that computer junk?) wife, Paula. I live in Paradise, Newfoundland and Labrador.
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3 Responses to Ubuntu/Debian and Broadcom BCM5762

  1. Anderson Fernandes says:

    Hi from Brazil! Same issue with those network cards on Proxmox. I’ll give a try.
    Nice blog, by the way. Thanks for the help.

  2. Tom says:

    Hello there, how much power does A10 consume?

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