On 3.12.2021 17.29, Greg KH wrote:

On Fri, Dec 03, 2021 at 07:22:57AM -0800, Dave Hansen wrote:

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On 12/3/21 6:31 AM, Mathias Nyman wrote:

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Can you please see if you can repro and fix this?

This all was with current 5.16-rc3 on a tigerlake nuc.

Also, perhaps you can update the guide on what sort of setup/cables
etc.. you need when either the host or the client is a usb3.1 usb-c only
device.

+ Mathias, maybe he still has a USB 3.0 debugging cable.

Should have at the office, I'll pick it up next week and try it out.

Is someone at Intel responsible for this thing? get_maintainer.pl
doesn't think so:

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$ perl scripts/get_maintainer.pl ./drivers/usb/early/xhci-dbc.c
Greg Kroah-Hartman [off-list ref] (supporter:USB SUBSYSTEM)
Mike Rapoport [off-list ref] (commit_signer:1/1=100%,authored:1/1=100%,added_lines:5/5=100%,removed_lines:5/5=100%)
Andrew Morton [off-list ref] (commit_signer:1/1=100%)
linux-usb@vger.kernel.org (open list:USB SUBSYSTEM)
linux-kernel@vger.kernel.org (open list)

Intel is the only one that has this hardware :(

I can reproduce this.
Looks like problems started when driver converted to readl_poll_timeout_atomic() in:

796eed4b2342 usb: early: convert to readl_poll_timeout_atomic()

Seems to hang when read_poll_timeout_atomic() calls ktime_* functions.
Maybe  it's too early for ktime.

After reverting that patch it works again for me.

-Mathias