[RPi5] WiFi Speed Drops to Zero by GUI Activity

    I've got a weird one.

    My wifi connection w/ my RPi5 was terrible and I suspected it was because of the geekworm aluminum heatsink case blocking the on-board wifi antenna https://www.amazon.com/dp/B0CNRGN4B7

    My solution was to solder an external wifi antenna onto the board and drill a hole in the case to mount it (https://www.amazon.com/dp/B0C8M53ZWL and https://www.amazon.com/dp/B082SHKT3Q )

    Sure enough wifi connects reliably now and transfer speeds using lftp are much better than before.

    I have a bizarre side effect though. if I try to use the RPi5 at all while a transfer is in progress, speed drops to zero almost immediately.

    My screen saver is set to "off/blank screen" and it works fine in that state, but the second I touch anything and the screen turns on, it happens.

    My guess is some sort of grounding issue, but I figured I'd ask here first in case anybody has run into this before.

    Could be an undervoltage issue. Post a log to be sure.

    Please provide a full debug log.

    How to post a log (wiki)

    1. Enable debugging in Settings>System Settings>Logging
    2. Restart Kodi
    3. Replicate the problem
    4. Generate a log URL (do not post/upload logs to the forum)

    use "Settings > LibreELEC > System > Paste system logs" or run "pastekodi" over SSH, then post the URL link
    Quote from fliz

    I have a bizarre side effect though. if I try to use the RPi5 at all while a transfer is in progress, speed drops to zero almost immediately.

    Fixing the network throughput probably shifted the bottleneck to the app writing to the SD card. You'll need to investigate with 'top' to see what's going on. There are probably caches within the LTFP server app. There are definitely caches in system memory and the filesystem. There's also invisible things internal to the SD card too. Something somewhere chokes /shrug

    fliz You're right, the PSU is fine.

    I think it's a problem with wrong RPi firmware (unknown/new hardware revision on RPi5):

    Code
    Mar 24 02:45:55.807760 LibreELEC kernel: rp1-pio 1f00178000.pio: error -ENOENT: failed to contact RP1 firmware
Mar 24 02:45:55.807790 LibreELEC kernel: rp1-pio: probe of 1f00178000.pio failed with error -2
...
Mar 24 02:45:55.817716 LibreELEC kernel: rp1-firmware: probe of rp1_firmware failed with error -110

    Try the latest LE 13 nightly.

    Quote from Da Flex

    I think it's a problem with wrong RPi firmware (unknown/new hardware revision on RPi5):

    This is harmless if you are not using PIO (and almost no one is).

    The next LE kernel bump will demote it to an warning.

    Updating the bootloader will also remove the complaint (but unlikely to affect this issue).

    Disabling trakt did nothing.

    Transfer speeds are like 20K/s, but as soon as the screen turns off it jumps to 2M/s or more. As soon as do anything that turns the screen back on, the speeds crash back down to sub 30K/s

    It's odd to me that this could be some sort of writing bottleneck. Why would the screen being on impact it?


    Quote from fliz

    My guess is some sort of grounding issue, but I figured I'd ask here first in case anybody has run into this before.

    If the outside of the antenna connector is making contact with the aluminium case, that could be the cause of your issues. As soon as the RPi starts doing stuff it could be coupling all kinds of electrical noise to the case. I'd try electrically isolating the antenna connector from the case. For testing purposes you could probably simply unscrew it and make sure it isn't touching the case with any exposed metal parts. If that does solve the issue, for a more permanent solution you could for example try enlarging the hole in the case, inserting a rubber grommer and mounting the connecter to that grommet.