Re: [PATCH v3 3/9] arm64: dts: amlogic: Used onboard usb hub reset on odroid c2

From: Ben Wolsieffer
Date: Sat Aug 05 2023 - 20:29:34 EST

On Sat, Aug 05, 2023 at 11:30:21PM +0200, Krzysztof Kozlowski wrote:
> On 02/08/2023 23:06, Ben Wolsieffer wrote:
> >
> > Hello,
> >
> > This patch breaks USB support on the ODROID-C2. As soon as the
> > onboard_usb_hub module is loaded, all USB devices disconnect.
> > Blacklisting onboard_usb_hub makes USB work as expected.
> >
> > I tried to reproduce the problem by manually toggling the reset line,
> > but the problem seems to be specific to this driver. When reset is
> > asserted manually, the devices disconnect, but they all enumerate again
> > as soon as reset is released.
> >
> > Also, I have been unable to make USB work again (until the next reboot)
> > even after unloading onboard_usb_hub.
> Wasn't this patch made exactly to fix USB support, not break it? I might
> be missing something but maybe this was not tested at all?
> Best regards,
> Krzysztof

I have been using USB on the ODROID-C2 for several years without issues.
It looks to me that this patch was designed to make reset control for
the hub more elegant, rather than fix a specific issue. The same change
was applied to several devices, so it seems plausible that it was not
tested on all of them.

Thanks, Ben