USB error on LS1046 platform

[Rob Herring]

+Laurentiu, Li

On Tue, Jan 27, 2026 at 09:21:38AM +0100, Alexander Wilhelm wrote:
> Hello developers,
> 
> I’m using an NXP LS1046A SoC with the integrated DWC3 USB controller in
> host mode. On Linux v5.5.167 my USB flash drive was detected and mountable.
> After upgrading to Linux v6.6.110 the USB flash drive is no longer
> recognized. If it is already plugged in during boot phase I get the
> following errors:
> 
>     xhci-hcd xhci-hcd.2.auto: Error while assigning device slot ID: Command Aborted
>     xhci-hcd xhci-hcd.2.auto: Max number of devices this xHCI host supports is 127
> 
> I have narrowed the issue down to the following commit:
> 
>     136975c33894e7b48a6007af0f4c25f423bbd1de
>     arm64: dts: ls1046a: make dma-coherent global to the SoC

It's best to send this to the author(s) of the commit.

Looks like it needs to be reverted or USB marked non-coherent. That's 
Shawn's responsibility to apply and the author to send a fix (unless 
you want to). The DT maintainers don't take .dts patches.

> 
> When I revert this commit, USB works perfectly on my system.
> 
> I have already asked on the `linux-usb` mailing list
> (https://lore.kernel.org/linux-usb/aTFr17xKxnWGG3vU@FUE-ALEWI-WINX/) and also
> forwarded the message to `linux-arm-kernel`, but I haven’t received any replies
> so far. Has anyone encountered this problem on the LS1046 or a similar platform?
> Any hints or experiences would be greatly appreciated.
> 
> 
> Best regards
> Alexander Wilhelm