Re: Regression in 5.19.0: USB errors during boot

[Alan J. Wylie]

at 08:23 on Sun 21-Aug-2022 Christoph Hellwig (hch@xxxxxx) wrote:

> On Thu, Aug 18, 2022 at 04:47:14PM +0200, Greg Kroah-Hartman wrote:
> > What is the output of the lspci -v for the USB 3 controller?
> > 
> > Christoph, any ideas?
>
> Well, with that commit it must be related to dma ops selection.
> As this appears to be an AMD system the options here are direct,
> amd_iommu and possibly amd_gart as the odd one in the mix.
>
> Alan, can you send me your .config?

I hope that with the following information there is no need for me to
do so.

It is indeed an old AMD CPU
  Model name:          AMD FX(tm)-4300 Quad-Core Processor
  CPU family:          21
  Model:               2

Comparing with another AMD system that doesn't show the problem,
I see that CONFIG_GART_IOMMU is only set on the one with the problem.

The configs have just had "make oldconfig" run on them for years, I
have no idea why one has it set.

Clearing it fixes the problem!

Thanks for the hint, although there is a still wider issue with this
regression.

$ diff .config.old  .config
353c353
< CONFIG_GART_IOMMU=y
---
> # CONFIG_GART_IOMMU is not set
4683d4682
< CONFIG_IOMMU_HELPER=y
4987d4985
< # CONFIG_IOMMU_DEBUG is not set
$

-- 
Alan J. Wylie                                          https://www.wylie.me.uk/

Dance like no-one's watching. / Encrypt like everyone is.
Security is inversely proportional to convenience