Re: [PATCH] usb: core: add USB_QUIRK_CONFIG_DESC_READ_255 for Razer BlackShark V3 Pro

[Charles D'Aoust]

You are correct, they are indeed the same. I apologize, I missed it.
---
Charles D’Aoust

---
Charles D’Aoust


On Mon, Jul 20, 2026 at 12:04 PM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Mon, Jul 20, 2026 at 11:01:26AM -0400, Charles Daoust wrote:
> > From: Charles D'Aoust <charles.daoust@xxxxxxxxx>
> >
> > The Razer BlackShark V3 Pro wireless headset dongle (1532:0577)
> > fingerprints its host during the first enumeration after power-on: if
> > the first GET_DESCRIPTOR(CONFIGURATION) request asks for 255 bytes, as
> > Windows does, the dongle enables its vendor HID command channel; if it
> > sees the 9-byte header-only read that Linux issues, it disables that
> > channel for the rest of the power session.  Audio still works in that
> > state, but battery reporting and all vendor commands are silently
> > ignored, and nothing short of removing power recovers the device:
> > resets, re-enumerations and byte-exact replays of complete Windows
> > control sessions were all verified not to help.
> >
> > Both read lengths are spec-compliant (the device truncates the reply
> > to wLength); the firmware was evidently only validated against the
> > larger request.  The kernel already accommodates this class of
> > firmware assumption during enumeration: hub_port_init() reads the
> > device descriptor with a 64-byte request because that is what Windows
> > does and what many devices expect.
> >
> > Add USB_QUIRK_CONFIG_DESC_READ_255, which makes usb_get_configuration()
> > request 255 bytes for the initial configuration descriptor read rather
> > than USB_DT_CONFIG_SIZE, apply it to 1532:0577, and expose it as
> > runtime quirk letter 'r'.  Devices without the quirk are unaffected.
> >
> > The trigger was isolated by single-variable bisection on otherwise
> > unmodified kernels: with only the widened initial read, the dongle's
> > vendor channel comes up enabled on a cold plug with no interface
> > drivers bound (bare enumeration only); without it, it never does.
> >
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Charles D'Aoust <charles.daoust@xxxxxxxxx>
> > ---
>
> Is this not the same as
>
> https://lore.kernel.org/linux-usb/20260717195336.98500-2-nikhilsolanke5@xxxxxxxxx/
>
> ?
>
> Alan Stern
>
> >  Documentation/admin-guide/kernel-parameters.txt |  3 +++
> >  drivers/usb/core/config.c                       | 13 ++++++++++---
> >  drivers/usb/core/quirks.c                       |  6 ++++++
> >  include/linux/usb/quirks.h                      |  3 +++
> >  4 files changed, 22 insertions(+), 3 deletions(-)
> >
> > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > index b5493a7f8..1bd138ba6 100644
> > --- a/Documentation/admin-guide/kernel-parameters.txt
> > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > @@ -8169,6 +8169,9 @@ Kernel parameters
> >                               q = USB_QUIRK_FORCE_ONE_CONFIG (Device
> >                                       claims zero configurations,
> >                                       forcing to 1);
> > +                             r = USB_QUIRK_CONFIG_DESC_READ_255 (initial
> > +                                     configuration descriptor read must
> > +                                     request 255 bytes, as Windows does);
> >                       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 cd3231d21..c7e21cc76 100644
> > --- a/drivers/usb/core/config.c
> > +++ b/drivers/usb/core/config.c
> > @@ -908,7 +908,7 @@ int usb_get_configuration(struct usb_device *dev)
> >  {
> >       struct device *ddev = &dev->dev;
> >       int ncfg = dev->descriptor.bNumConfigurations;
> > -     unsigned int cfgno, length;
> > +     unsigned int cfgno, length, first_read_len;
> >       unsigned char *bigbuffer;
> >       struct usb_config_descriptor *desc;
> >       int result;
> > @@ -938,7 +938,14 @@ int usb_get_configuration(struct usb_device *dev)
> >       if (!dev->rawdescriptors)
> >               return -ENOMEM;
> >
> > -     desc = kmalloc(USB_DT_CONFIG_SIZE, GFP_KERNEL);
> > +     /*
> > +      * Some devices (see USB_QUIRK_CONFIG_DESC_READ_255) malfunction unless
> > +      * the initial configuration descriptor read requests 255 bytes, as
> > +      * Windows does.  Only the header is consumed here either way.
> > +      */
> > +     first_read_len = (dev->quirks & USB_QUIRK_CONFIG_DESC_READ_255) ?
> > +                      255 : USB_DT_CONFIG_SIZE;
> > +     desc = kmalloc(first_read_len, GFP_KERNEL);
> >       if (!desc)
> >               return -ENOMEM;
> >
> > @@ -946,7 +953,7 @@ int usb_get_configuration(struct usb_device *dev)
> >               /* We grab just the first descriptor so we know how long
> >                * the whole configuration is */
> >               result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno,
> > -                 desc, USB_DT_CONFIG_SIZE);
> > +                 desc, first_read_len);
> >               if (result < 0) {
> >                       dev_err(ddev, "unable to read config index %d "
> >                           "descriptor/%s: %d\n", cfgno, "start", result);
> > diff --git a/drivers/usb/core/quirks.c b/drivers/usb/core/quirks.c
> > index 87ee2d938..c8f71b825 100644
> > --- a/drivers/usb/core/quirks.c
> > +++ b/drivers/usb/core/quirks.c
> > @@ -142,6 +142,9 @@ static int quirks_param_set(const char *value, const struct kernel_param *kp)
> >                               break;
> >                       case 'q':
> >                               flags |= USB_QUIRK_FORCE_ONE_CONFIG;
> > +                             break;
> > +                     case 'r':
> > +                             flags |= USB_QUIRK_CONFIG_DESC_READ_255;
> >                       /* Ignore unrecognized flag characters */
> >                       }
> >               }
> > @@ -496,6 +499,9 @@ static const struct usb_device_id usb_quirk_list[] = {
> >       /* Razer - Razer Blade Keyboard */
> >       { USB_DEVICE(0x1532, 0x0116), .driver_info =
> >                       USB_QUIRK_LINEAR_UFRAME_INTR_BINTERVAL },
> > +     /* Razer - Razer BlackShark V3 Pro wireless headset dongle */
> > +     { USB_DEVICE(0x1532, 0x0577), .driver_info =
> > +                     USB_QUIRK_CONFIG_DESC_READ_255 },
> >       /* Razer - Razer Kiyo Pro Webcam */
> >       { USB_DEVICE(0x1532, 0x0e05), .driver_info = USB_QUIRK_NO_LPM },
> >
> > diff --git a/include/linux/usb/quirks.h b/include/linux/usb/quirks.h
> > index b3cc7beab..02de5ed48 100644
> > --- a/include/linux/usb/quirks.h
> > +++ b/include/linux/usb/quirks.h
> > @@ -81,4 +81,7 @@
> >  /* Device claims zero configurations, forcing to 1 */
> >  #define USB_QUIRK_FORCE_ONE_CONFIG           BIT(18)
> >
> > +/* initial configuration descriptor read must request 255 bytes (Windows) */
> > +#define USB_QUIRK_CONFIG_DESC_READ_255               BIT(19)
> > +
> >  #endif /* __LINUX_USB_QUIRKS_H */
> > --
> > 2.55.0
> >
> >