How to roll back kernel driver for xhci-hcd

bgii2000 · 11-03-2021, 03:58 PM

I have a VIA VL805 4 port USB PCIe card that works fine in the latest Linux Mint, but not in the latest Debian.

Using

Code:

sudo lsusb -v

I can see in In both cases linux is loading the default xhci-hcd driver that ships with the kernel, no funny business there. The only difference I can see is that Mint is using Linux 5.4.0-89-generic, whereas Debian is using Linux 5.10.0-9-amd64.

In Mint, the card works fine, in Debian dmseg shows:

Code:

xhci_hcd 0000:06:00.0: xHCI host controller not responding, assume dead

Is there any way to tell Debian to boot with an older kernel, or even better, just the xhci-hcd part of the older kernel?

bgii2000 · 11-04-2021, 01:27 AM

Ok, I built a custom kernel (oldconfig on the one that came with bullseye) but based on the 5.4 source rather than the 5.10. The card works again. But is this... the right way to do this? Haven't I broken a bunch of stuff?

pan64 · 11-04-2021, 01:44 AM

Quote:

Originally Posted by bgii2000

Ok, I built a custom kernel (oldconfig on the one that came with bullseye) but based on the 5.4 source rather than the 5.10. The card works again. But is this... the right way to do this? Haven't I broken a bunch of stuff?

Without details hard to say anything. It looks like the driver is broken in 5.10 and you need to report it or check if it was already (or will be) fixed.

bgii2000 · 11-04-2021, 05:20 PM

That would my first time doing so. But I would love to learn. Can you point the way? Where do I submit a bug report? What version of the kernel should I submit it to(for?)? What should I bring with me?

I KnowNothingJonSnow but I get the idea that there is a... 'maintainer' somewhere whose attention I need to acquire. Is that... USB? Via? Xhci?

pan64 · 11-06-2021, 03:34 AM

I would probably start here: https://kernelnewbies.org/ or https://bugzilla.kernel.org/

bgii2000 · 11-06-2021, 11:37 AM

Excellent. Thanks.

business_kid · 11-06-2021, 01:02 PM

Quote:

Originally Posted by bgii2000

That would my first time doing so. But I would love to learn. Can you point the way? Where do I submit a bug report? What version of the kernel should I submit it to(for?)? What should I bring with me?

I KnowNothingJonSnow but I get the idea that there is a... 'maintainer' somewhere whose attention I need to acquire. Is that... USB? Via? Xhci?

If you go through the bug reporting interface on kernel.org, it gets to the relevant guy. Before you file the bug, get yourself the most recent stable linus kernel release, and report the bug on that; you can mention which earlier version you first found it on.

You're needed because you have hardware that shows the bug they can't see. So you need to test & feed back on all patches. It helps to have a thick skin, because it will probably be needed

. You're expected to do the work required, which can be imposing.

EDIT: About 20 years back, I had a bug on what transpired to be an early version of a VIA chip, and they changed the chip hardware without informing their own devs

The work on that was imposing.