2

I put

gpu_mem=512

in /boot/config.txt (which file I had to create), and it had no effect.

grep memory /var/log/Xorg.0.log

returned only 2,839kB:

[   132.909] (II) FBDEV(0): hardware: BCM2708 FB (video memory: 2839kB)

Is there a newer way to change GPU memory? I'm on SARPi current with Linux kernel 4.9.70-v7-arm.

There was no /boot/config.txt file originally, but I do have a /boot/boot/config-armv7-5.4.31 file. What is that?

  • Sorry I don't have enough reputation to comment, but can I know what OS you are using that you didn't have a config.txt file? I always have one to edit and modify which is why I am asking. – brantchyoga Apr 25 at 17:29
  • I'm using Slackware ARM on a Raspberry Pi (SARPi). It used to have a config.txt file (when I used it a few years ago), but I think some run of rpi-udate since then changed things. – Geremia Apr 25 at 18:35
  • The Xorg framebuffer driver is a software construct and not synonymous with the hardware. Edit in the output from vcgencmd get_mem gpu. raspberrypi.org/documentation/raspbian/applications/vcgencmd.md – goldilocks Apr 25 at 19:31
  • @goldilocks I'm not using Raspbian, so I don't have vcgencmd. Is there another to get it? – Geremia Apr 25 at 20:13
1

The canonical way to get the GPU memory is with vcgencmd:

vcgencmd get_mem gpu 

If your distro doesn't provide that, you can build it with the source tree that also includes raspicam and the userspace GPU libs:

https://github.com/raspberrypi/userland

However, you probably don't need to go to that much trouble if you just want to confirm the split is set, because for every MB of GPU allocated you have one less MB of RAM, and there are all kinds of ways to check that (try free -h and check the top row total).

grep memory /var/log/Xorg.0.log returned only 2,839kB:

[ 132.909] (II) FBDEV(0): hardware: BCM2708 FB (video memory: 2839kB)

I don't think that number has much to do with the GPU/RAM split, and I don't think "video memory" refers to actual physical video memory. It might WRT other Xorg drivers for different hardware, but the framebuffer driver is for a software construct provided by the kernel (FBDEV = framebuffer device).1

I don't have any pis running X right now to check, but looking through logs from old backups of systems where I did at least occasionally, that would also have been running cameras (requiring >= 128 MB GPU), that number varies between 1500 kB and 7100 kB.

Finally, the GPU requires a minimum of 16 MB. You can't set it less than that, so it must be at least 16384 kB.


  1. Looking at the Xorg log for this laptop, which has a dual video card one part of which is a beefy nvidia thing, there's no numbers at all reported for video memory, although I do seem to believe I've seen it before.
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