Fixing low-speed USB keyboard detection

Soeren Moch smoch at
Sun Mar 1 18:46:32 CET 2020

Hi Stefan,

please do not top-post.

On 29.02.20 13:42, Stefan wrote:
> Hello Soeren!
> It will take me some time to prepare a proper patch, I just found the documentation of your patman tool. I am using Guix and created a package definition for U-Boot with these three fixes using regexp substitutions.
I never used these tools, just git and git-send-email. But maybe they
can be helpful for you.
> My time is quite limited for this weekend. I guess that you would be much faster preparing these three simple changes as a patch. So I would be glad, if you prepare a patch.
If you are not familiar with the u-boot patch submitting procedure, and
want to learn how to do it properly, then I'm happy to help.
If you just have no time to do it right, I certainly have better things
to do on _my_ weekend than writing patches for bugs that I don't see on
hardware I do not own, sorry.
> A proper commit message could be this: “This patch works around issues of low-speed USB keyboards with the dwc2 USB interface. There was a need to press a key when "USB0: scanning bus 0 for devices..." was printed or otherwise there was the error "Timeout poll on interrupt endpoint" and the keyboard was not usable. This patch reverts the workaround from 5da2dc9789abecb1b018beb0c93f4c38c2985bc6 for non-working keyboards.”
Without looking into this in detail, I would expect this needs to be
sent as series of 3 patches to 2 different maintainers, and the u-boot
mailing list, of course. And please provide your full name for sign-off.

> Stefan
>> Am 29.02.2020 um 13:04 schrieb Soeren Moch <smoch at>:
>> On 29.02.20 00:46, Marek Vasut wrote:
>>> On 2/26/20 12:04 PM, Soeren Moch wrote:
>>>> Adding Marek as USB maintainer. Otherwise this non-patch-email may get
>>>> lost when sent to the mailing list only.
>>> Well, can you send these as proper patches ?
>> Well, I can try to make a proposal for patches. But I cannot test
>> something since I neither own such D-Link DBT-120 Bluetooth Adapter, nor
>> a Raspberry Pi 3b as host system. I'm also not familiar with the details
>> of event polling / interrupt message NYET handling in u-boot, so
>> probably will not come up with a good commit message about this. I also
>> cannot judge which workaround or revert of such is appropriate.
>> Stefan, can you convert your fixes to proper patches yourself, or do you
>> want me to send a first proposal?
>> Thanks,
>> Soeren
>>>> Soeren
>>>> On 25.02.20 18:45, Stefan wrote:
>>>>> Hello!
>>>>> I own a D-Link DBT-120 Bluetooth Adapter, which has a CSR firmware running in a so called “HID proxy mode”. This firmware pretends to be a USB keyboard (and mouse) and thus allows to use a Bluetooth keyboard in U-Boot.
>>>>> Unfortunately it acts as a low-speed device and there seems to be some well known troubles about low-speed USB keyboards. There is a FAQ entry for openSUSE about this:
>>>>> I spend some effort to solve this issue. There are three tiny changes to get my Bluetooth keyboard working reliably as a low-speed USB keyboard.
>>> [...]

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