Illuminated Computing

GeForce RTX 5070 Ti on Linux (Debian 13)

2026-01-02T00:00:00Z

I got a GeForce RTX 5070 Ti GPU for Christmas. I want to do some AI stuff with it. Maybe I’ll have something about that to post soon. But getting it to work on my system was really a chore! I’m running Debian 13 with a ROG STRIX B550-F motherboard (not the wifi version).

After I put it in and tried to boot, I saw Grub’s selection screen, but almost immediately my monitor went black, and within 10 or 20 seconds it lost its connection entirely.

By adding an extra echo line after initrb in grub I could see that at least that part was running. But it was dying soon after, and I had no messages to diagnose the problem. Doing something like journalctl -b -1 gave nothing (or rather info from the boot prior).

Adding modeset stuff to grub didn’t help. Adding noacpi or pci=noacpi didn’t help. Turning off ACPI altogether with acpi=off let me boot though. I didn’t have working graphics, but I could Ctrl-Alt-F3 to a console and run commands.

Even after installing nVidia’s driver, I didn’t have a working display. I followed their instructions for the open-source driver, which gave me version 590.48.01. (Their old closed-source driver doesn’t support newer cards like the 5070 Ti.) This reddit thread helped too. Basically I did this:

apt-get install linux-headers-amd64
apt-get install linux-headers-$(uname -r)
wget https://developer.download.nvidia.com/compute/cuda/repos/debian13/x86_64/cuda-keyring_1.1-1_all.deb
dpkg -i cuda-keyring_1.1-1_all.deb
apt-get update
apt-get install nvidia-open

Then I could run nvidia-smi, and lsmod | awk 'NR==1||/nvid/' showed nvidia_uvm, nvidia, and drm. Also I could see from mokutil --sb-state that I was running with SecureBoot disabled, which Google AI thinks is a good idea.

But my display problems continued. When I ran startx by hand I could see a segfault in /var/log/Xorg.0.log. Later I got this to go away (perhaps it was adding grub commands to blacklist nouveau sooner?), and then X would start, and with pstree I could see that xfce was running and even restoring commands from my session, like terminals and firefox. But the display wouldn’t switch: I was still looking at the console, with some messages printed by X.

In the boot log I saw errors about not finding the DRM device, and before that there were messages about IRQ problems for the PCI device. There was a recommendation to use pci=biosirq, but that didn’t help. (I think that hint is for really old systems anyway.) I figured probably acpi=off was messing things up.

I tried upgrading my motherboard BIOS. It was a few years out-of-date. I installed the latest version (3635, published 2025-11-06 with build date 2025-09-30). After unzipping, I renamed the file to RSB550FG.CAP. Then I formatted an 8GB USB drive with mkfs.vfat --mbr=yes -I -F 32 /dev/disk/by-id/usb-SanDisk_Cruzer_Fit_4C532000030816101033-0\:0. Then I copied the file to the root of the drive, ran sync, and yanked the USB stick. With case power on but the computer off, I stuck the USB into the Flash BIOS port in the back and held down the Flash BIOS button for a few seconds. When I let go, the USB activity light started blinking. If I shaded the motherboard panel I could see that the Flash BIOS light was blinking too. So I let it run for 5 or 10 minutes, and when I checked the blinking had stopped. I booted, and the BIOS still worked!

Somehow this made grub much slower. Every keystroke took a second or two to register, and I easily lost letters. I tried some BIOS tweaks, like turning off Legacy USB support. But the only thing that worked was changing GRUB_GFXMODE to 1024x768. Actually 640x480 was even better, but all the lines wrapped and it was unreadable. I’m pretty sure a lower resolution shouldn’t be needed. I think flashing the BIOS wiped all my old settings, so maybe there is some better way to restore grub’s performance, but I haven’t found it yet.

Anyway, the BIOS upgrade didn’t solve my problems. Allowing ACPI still caused a failure right after starting the kernel. I suspected that a proper fix to acpi=off would do the trick. I found this article about using the 5070 Ti on Linux, and I started changing BIOS settings. The issue turned out to be “Above 4G Encoding” (under “Advanced > PCI Subsystem Settings”). For me it was disabled. When I enabled it, suddenly everything worked.

That’s it. I haven’t tried installing cuda-toolkit yet, but that’s next. I’ve had an AMD card for years. A year or two ago I got ROCm compiled, after much struggle, but pytorch would just segfault. I’m excited to play around with AI a bit now.

Anyway, “Above 4G Encoding” was definitely not in Google AI’s many, many recommendations as I searched for solutions, so perhaps this blog entry will go into its next training and help someone out.

rsync and --exclude-from

2010-03-20T00:00:00Z

Lately I’ve been looking for a better backup solution, and I settled on rsync. If you want a good tutorial, you can find one easily enough by googling. But I had a lot of trouble finding good documentation about the --exclude-from option. What I found was either too cursory or just plain wrong. So I did some tests, and here are my results. I’m pleased to say that rsync’s --exclude-from option has very full functionality!

This option names a file, as in --exclude-from=my-excludes.txt. That file contains a list of patterns, and if one of the patterns matches a given file or directory, rsync leaves that file/directory out of the backup.

These patterns may be full filenames, as in log, or they may use wildcards, as in *.bak. If a directory is excluded, then all the files within it are excluded, too. (This sounds obvious, but I’ve seen other programs with exclude files that just leave out the directory!)

You can even include bits of a path in your exclude file to further limit what gets excluded. For instance, if you say photos/thumb, then the thumb directory will be excluded whenever it appears inside a folder called photos. It will not be excluded if it appears in, say, body-parts. Also, rsync will still include your photos folders; just their thumbs folders will be left out.

Finally (and this is the part I was really interested in and found wrongly-documented elsewhere), you can include specific paths. You do this by starting the path with a slash: /root/tmp. This forward slash does not indicate a file at the root of your filesystem, like a normal unix path. Rather it tells rsync to anchor this path to the base of the top-level source folder.

Note that if you’re using this feature, you must use it consistently with how you specify your source folder. Remember that in rsync, if you name your source folder without a trailing slash, rsync copies that folder and everything in it, whereas if you give it a trailing slash, rsync copies just the folders’ contents. Well, anchored paths in the --exclude-from file must take account of this. Suppose your source folder is root. Then your excludes file would have a line like /root/tmp. If if your source folder is root/, then your excludes file needs a line like /tmp.

To put this all into an example, suppose you have this file structure and you want to exclude all the red files:

root/
     important.txt
     important.txt.bak
     mysql/
           ecom.db
           log/mysql.log
     photos/thumb/
     tmp/note.txt
     www/
         index.html
         log/www.log
         photos/thumb/
         tmp/index-ver2.html

In other words, you want to exclude: * All *.bak files. * All log directories. * All photo/thumb directories. * The top-level tmp directory.

Then you could either call rsync like this:

rsync -avz --exclude-from=excludes.txt root backups

with excludes.txt as follows:

*.bak
log
photos/thumb
/root/tmp

Or you could call rsync like this:

rsync -avz --exclude-from=excludes.txt root/ backups

with an excludes.txt like this:

*.bak
log
photos/thumb
/tmp

UPDATE: One more note: You might think that ending a line in the excludes file with a trailing slash would work analogously to naming a source directory with a trailing slash: “include this directory but not its contents.” That way if you were backing up your whole filesystem, you could have a line like /mnt/ that would create a /mnt directory but ignore all its contents. But in fact, rsync just seems to ignore trailing slashes in the excludes file. If you want to exclude everything in the /mnt directory, you need a line like this instead: /mnt/*.

Sort by File Size with du

2010-03-02T00:00:00Z

Here is a handy Perl script I wrote a while back to sort the output from du -sh by file size. The standard sort command can’t do this because it doesn’t know how to compare values like “488M” and “5.0K.” My code will sort any lines where this values appear in the first field. I’m sure the Perl could be more compressed, but keeping it easy to read like this is more my style:

#!/usr/bin/perl -w
use strict;
use Data::Dumper;

my @lines;

while (<>) {
  chomp;
  push @lines, [unabbrev($_), $_];
  # print "$_: ", unabbrev($_), "\n";
}

# print Dumper \@lines;

for my $line (reverse sort { return $a->[0] <=> $b->[0] } @lines) {
  print $line->[1], "\n";
}

sub unabbrev {
  my $val = shift;
  if ($val =~ m/^\s*(\d+(\.\d+)?)([KMGB]?)/) {
    if ($3 eq 'K') {
      $val = $1 * 1000;
    } elsif ($3 eq 'M') {
      $val = $1 * 1000000;
    } elsif ($3 eq 'G') {
      $val = $1 * 1000000000;
    } else { # B or nothing
      $val = $1;
    }
  }
  return $val;
}

It’d be fun to re-write this in ruby—or even better, add it as a feature to GNU sort.

UPDATE: Reading the documentation for GNU coreutils (which contains sort), I see that sort does have an -h option (for –human-numeric-sort). Strangely, this option is not documented in the man page on Ubuntu 9.10 and is unrecognized by /usr/bin/sort. I guess I’ve got an old version.

If anyone is looking for a small open source project, sort’s implementation of this option could still be improved. Right now, according to the online docs, “values with different precisions like 6000K and 5M will be sorted incorrectly.” It’d be great if it fully implemented the rules for block size used by other coreutils programs.

rtouch

2009-03-08T00:00:00Z

By the way …

Upgrading Wordpress is annoying! There was lots of “delete this folder–except for file x and folder y.” Because of how I organize things, at one point I found it useful to write a recursive touch script. Here it is:

#!/usr/bin/perl -w
use strict;
use File::Find;

my @dirs = @ARGV ? @ARGV : ('.');

find sub {
    system("touch", $_);
}, @dirs;

It’s pretty simple: for instance, it doesn’t pass along any options to the touch program. But I thought I’d put that off until I can rewrite it in ruby. This Perl version was just because I needed it done quick.