Re: [PATCH v2] Revert "usb: gadget: composite: fix OS descriptors w_value logic"

From: Peter Korsgaard
Date: Thu Nov 14 2024 - 05:42:09 EST


>>>>> "Elson" == Elson Roy Serrao <quic_eserrao@xxxxxxxxxxx> writes:

> From: Michal Vrastil <michal.vrastil@xxxxxxxxxxxxx>
> This reverts commit ec6ce7075ef879b91a8710829016005dc8170f17.

> Fix installation of WinUSB driver using OS descriptors. Without the
> fix the drivers are not installed correctly and the property
> 'DeviceInterfaceGUID' is missing on host side.

> The original change was based on the assumption that the interface
> number is in the high byte of wValue but it is in the low byte,
> instead. Unfortunately, the fix is based on MS documentation which is
> also wrong.

> The actual USB request for OS descriptors (using USB analyzer) looks
> like:

> Offset 0 1 2 3 4 5 6 7
> 0x000 C1 A1 02 00 05 00 0A 00

> C1: bmRequestType (device to host, vendor, interface)
> A1: nas magic number
> 0002: wValue (2: nas interface)
> 0005: wIndex (5: get extended property i.e. nas interface GUID)
> 008E: wLength (142)

> The fix was tested on Windows 10 and Windows 11.

> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: ec6ce7075ef8 ("usb: gadget: composite: fix OS descriptors w_value logic")
> Signed-off-by: Michal Vrastil <michal.vrastil@xxxxxxxxxxxxx>
> Signed-off-by: Elson Roy Serrao <quic_eserrao@xxxxxxxxxxx>

Acked-by: Peter korsgaard <peter@xxxxxxxxxxxxx>

--
Bye, Peter Korsgaard