Re: [PATCH] usb: core: new quirk to handle devices with zero configurations

[Jie Deng]

在 2026/2/26 23:30, Alan Stern 写道:
> On Thu, Feb 26, 2026 at 05:47:37PM +0800, Jie Deng wrote:
> > Some USB devices incorrectly report bNumConfigurations as 0 in their
> > device descriptor, which causes the USB core to reject them during
> > enumeration.
> > logs:
> > usb 1-2: device descriptor read/64, error -71
> > usb 1-2: no configurations
> > usb 1-2: can't read configurations, error -22
> >
> > However, these devices actually work correctly when
> > treated as having a single configuration.
> >
> > Add a new quirk USB_QUIRK_FORCE_ONE_CONFIG to handle such devices.
> > When this quirk is set, assume the device has 1 configuration instead
> > of failing with -EINVAL.
> >
> > This quirk is applied to the device with VID:PID 5131:2007 which
> > exhibits this behavior.
> >
> > Signed-off-by: Jie Deng <dengjie03@xxxxxxxxxx>
> > ---
> >   Documentation/admin-guide/kernel-parameters.txt | 3 +++
> >   drivers/usb/core/config.c                       | 7 ++++++-
> >   drivers/usb/core/quirks.c                       | 5 +++++
> >   include/linux/usb/quirks.h                      | 3 +++
> >   4 files changed, 17 insertions(+), 1 deletion(-)
> >
> > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > index cb850e5290c2..63e6d3ebbd7a 100644
> > --- a/Documentation/admin-guide/kernel-parameters.txt
> > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > @@ -8183,6 +8183,9 @@ Kernel parameters
> >   				p = USB_QUIRK_SHORT_SET_ADDRESS_REQ_TIMEOUT
> >   					(Reduce timeout of the SET_ADDRESS
> >   					request from 5000 ms to 500 ms);
> > +				r = USB_QUIRK_FORCE_ONE_CONFIG (Device
> > +					claims zero configurations,
> > +					forcing to 1);
> >   			Example: quirks=0781:5580:bk,0a5c:5834:gij
> >   
> >   	usbhid.mousepoll=
> > diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
> > index 1cd5fa61dc76..f60fed224cbb 100644
> > --- a/drivers/usb/core/config.c
> > +++ b/drivers/usb/core/config.c
> > @@ -927,7 +927,12 @@ int usb_get_configuration(struct usb_device *dev)
> >   		dev->descriptor.bNumConfigurations = ncfg = USB_MAXCONFIG;
> >   	}
> >   
> > -	if (ncfg < 1) {
> > +	if (dev->quirks & USB_QUIRK_FORCE_ONE_CONFIG) {
> > +		dev_info(ddev, "Device claims zero configurations,
> > +				forcing to 1\n");
> > +		dev->descriptor.bNumConfigurations = 1;
> > +		ncfg = 1;
> What if a device claims to have 2 configurations but the flag is set?
> This will cause the kernel to ignore the second configuration.

Thank you for your reply. I will modify the judgment logic and

generate a new version of the patch.

Jie Deng

> > +	} esle if (ncfg < 1) {
> -----------^^
>
> Clearly you never compiled this code.
>
> Alan Stern