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ucsi_acpi USBC000:00: unknown error 256 #185
Description
Device Information
Framework 13 AMD Ryzen AI 9 HX 370, Ubuntu 25.10 on kernel 6.17.0-14-generic
System Model or SKU
Please select one of the following
- Framework Laptop 12 (13th Gen Intel® Core™)
- Framework Laptop 13 (11th Gen Intel® Core™)
- Framework Laptop 13 (12th Gen Intel® Core™)
- Framework Laptop 13 (13th Gen Intel® Core™)
- Framework Laptop 13 (AMD Ryzen™ 7040 Series)
- Framework Laptop 13 (AMD Ryzen™ AI 300 Series)
- Framework Laptop 13 (Intel® Core™ Ultra Series 1)
- Framework Laptop 16 (AMD Ryzen™ 7040 Series)
- Framework Laptop 16 (AMD Ryzen™ AI 300 Series)
- Framework Desktop (AMD Ryzen™ AI 300 PRO Series)
BIOS VERSION
03.05
DIY Edition information
If you are experiencing an issue on a DIY system, Please also fill out the memory and storage devices you are using.
Memory: 2x A-data AD5S560048G-SF2 5600 MT/s from Framework
Storage: WD BLACK SN850X 4000GB
Standalone Operation (Laptop Only)
Are you running your mainboard as a standalone device. Is standalone mode enabled in the BIOS?
- Yes
- No
Describe the bug
Laptop is connected to an external monitor via USB-C, powered via the same cable via PD.
dmesg shows
[ 3.515902] ucsi_acpi USBC000:00: unknown error 256
[ 3.984035] ucsi_acpi USBC000:00: unknown error 256
[ 4.684068] ucsi_acpi USBC000:00: unknown error 256
Looks related to #3 but there is no CABLE-failed-related error messages, so it's better to open a new report.
The system seems unaffected and boots and works normally.
Steps To Reproduce
Steps to reproduce the behavior:
- Boot the machine; the error seems to be always there
Expected behavior
There should be no errors in dmesg.
Operating System (please complete the following information):
- OS/Distribution: Ubuntu
- Version: 25.10
- Linux Kernel Version:
Linux mavi-fw 6.17.0-14-generic #14-Ubuntu SMP PREEMPT_DYNAMIC Fri Jan 9 17:01:16 UTC 2026 x86_64 GNU/Linux
Additional context
Not sure whether the errors are always present or whether they're random.
Activity
mvysny commentedon Feb 26, 2026
Rebooting with the USB-C/external-monitor/PD cable unplugged, the error is still present in dmesg:
themkoi commentedon Mar 3, 2026
I have the same issue on the Framework Laptop 16 (AMD Ryzen™ 7040 Series) on bios 4.03 and kernel 6.19.4-2 during boot and when I reconnect the charger also randomly the charger stops charging for a second while also showing this error I dont know if the charging getting dropped is related to this error tho
JohnAZoidberg commentedon Mar 4, 2026
This error message can be safely ignored, it is not related to charger not working.
It says that the kernel is unable to figure out the cable properties. Our firmware currently does not pass this information correctly to the kernel.
We have fixed this for some cases but some more cases remain.
This error is a good indication though for a plug/unplug event. If you see this when you are not plugging/unplugging anything that means something is going wrong with the PD negotiation.
Yes
For this it would be useful to have a separate issue. And you can please capture some EC logs using
framework_tool --console followwhen you are plugging in the charger.valvin1 commentedon Mar 25, 2026
I'm having similar issue on the same platform running fedora. From user perspective my usb C slot is not working anymore. It is not the first time I detect my charger is not working. Don't know if it is hardware or software related? Let me know if I can help.
valvin1 commentedon Mar 27, 2026
here is framework_tool logs when I plug a device on usb port that generate the error 256:
i'm in last bios version 0.3.5
and current kernel is
6.19.9-200.fc43.x86_64bmp commentedon May 10, 2026
I have the same issue with the following system information:
In addition to
ucsi_acpi USBC000:00: unknown error 256, I also noticedBluetooth: hci0: Opcode 0x0401 failed: -16. When I try to access the 1tb expansion card, i get the following:However, the same USB-C 1tb expansion card works flawlessly without such messages on the Framework 13 11th Gen Intel i5.
smlx commentedon Jun 13, 2026
I'm also seeing this sometimes when plugging my yubikey directly into a USB-C port. The yubikey is not functioning correctly after this error starts appearing. Plug/unplug doesn't seem to help.
jcdutton commentedon Jul 24, 2026
The ucsi_acpi: unknown error 256 can be caused by multiple different causes.
I am aware of one where the Linux OS makes a UCSI request (GET_PDOS command 0x10) for the PDOs of say the FW 16 Power supply.
The OS makes an ACPI request to the EC. The EC then requests it from the USB PD chip.
There are 7 PDOs. The first command 0x10 with offset 0 works, and retrieves the first 4 PDOs.
The second command 0x10 with offset 4 fails, fails to retrieve any PDOs. The USB-PD chip resets, and the OS returns error 256.
It would be really helpful if FW fixed some of the USB PD firmware bugs, to make it a little less unstable.
The USB PD firmware has various bugs in it.
Another is the "sudo lsusb -v" that also crashes the USB-PD chip.
ToxicFrog commentedon Aug 20, 2026
I'm having the same issue on the FW16 (Ryzen AI 5 340), with bios 04.01, PD controller firmware 0.0.22, and kernel 6.18.40 -- under certain circumstances the system behaves as if the cable is being briefly unplugged and then plugged back in, even though it's not. This is using the official 100W adapter.
It's correlated with certain kinds of load; it doesn't happen when I am (e.g.) compiling something or playing most games, but I can trigger it once fairly reliably by switching back to Steam after it's lost focus, and loading up Mahjong Soul causes it to happen every few seconds until I either close the tab or unplug the cable.
Each time there are two entries in the dmesg log:
And here's
framework_tool(n.b. battery is configured in bios to stop charging at 80%, since this machine spends most of its time plugged in):ascpial commentedon Oct 27, 2026
I'm having the same issue: when trying to connect my Nitrokey 3C, I get the following error in dmesg and the key does not get recognized by pcsc:
It happens extremely consistently: I never got gpg to work with the key.
That said, the passkey feature of the key works without issues, so this error my not be the cause.
EDIT : the error was not the cause, I heavily misconfigured udev and forgot about it...
boozedog commentedon Nov 10, 2026
Framework 16 (AMD Ryzen 7040, BIOS 04.05), kernel 7.2.15-zen1. After error 256 on plug-in, sysfs reported a 5 V / 5 A contract while the pack was charging at ~27–33 W, so the reported PDO was wrong, not just missing cable identity. The top advertised PDO also flapped between 20 V/3.25 A, 20 V/4.5 A, and 20 V/5 A across reconnects. No EPR PDO was ever returned.
quinchou77 commentedon Nov 11, 2026
This error will be resolved in the 4.03 BIOS, with the beta release scheduled for around November 20th.
jfoliveiraramos commentedon Nov 13, 2026
Will this also target the 13 Pro?