From: Mattijs Korpershoek <mkorpershoek@kernel.org>
To: Marek Vasut <marex@nabladev.com>, u-boot@lists.denx.de
Cc: Marek Vasut <marex@nabladev.com>,
Lukasz Majewski <lukma@nabladev.com>,
Mattijs Korpershoek <mkorpershoek@kernel.org>,
Simon Glass <sjg@chromium.org>, Tom Rini <trini@konsulko.com>
Subject: Re: [PATCH] cmd: ums: Set Device Descriptor iSerial based on serial# env variable
Date: Mon, 15 Jun 2026 09:18:20 +0200 [thread overview]
Message-ID: <875x3ki85f.fsf@kernel.org> (raw)
In-Reply-To: <20260613025510.134239-1-marex@nabladev.com>
Hi Marek,
Thank you for the patch.
On Sat, Jun 13, 2026 at 04:54, Marek Vasut <marex@nabladev.com> wrote:
> The DFU code currently sets the content of "serial#" environment
> variable into Device Descriptor iSerial field. This is useful when
> there are multiple devices connected to the same host PC and they
> have to be told apart. Replicate the same behavior in the UMS code.
>
> Example without serial# set, which is the original behavior:
> "
> u-boot=> ums 0 mmc 1
> UMS: LUN 0, dev mmc 1, hwpart 0, sector 0x0, count 0x1d5a000
>
> $ dmesg -w
> ...
> usb 5-2.3.7: New USB device found, idVendor=0525, idProduct=a4a5, bcdDevice=7e.a7
> usb 5-2.3.7: New USB device strings: Mfr=1, Product=2, SerialNumber=0
> usb 5-2.3.7: Product: USB download gadget
> usb 5-2.3.7: Manufacturer: Vendor
> <------------------------------- NOT HERE
> usb-storage 5-2.3.7:1.0: USB Mass Storage device detected
> ...
>
> $ lsusb -vd 0525:a4a5
>
> Bus 005 Device 051: ID 0525:a4a5 Netchip Technology, Inc. Linux-USB File-backed Storage Gadget
> Negotiated speed: High Speed (480Mbps)
> Device Descriptor:
> bLength 18
> bDescriptorType 1
> bcdUSB 2.00
> bDeviceClass 0 [unknown]
> bDeviceSubClass 0 [unknown]
> bDeviceProtocol 0
> bMaxPacketSize0 64
> idVendor 0x0525 Netchip Technology, Inc.
> idProduct 0xa4a5 Linux-USB File-backed Storage Gadget
> bcdDevice 7e.a7
> iManufacturer 1 Vendor
> iProduct 2 USB download gadget
> iSerial 0 <------------------------------- NOT HERE
> ...
> "
>
> Example with serial# set to 1234abcd, which is the optional new behavior:
> "
> u-boot=> setenv serial# 1234abcd <------------------------------ HERE
> u-boot=> ums 0 mmc 1
> UMS: LUN 0, dev mmc 1, hwpart 0, sector 0x0, count 0x1d5a000
>
> $ dmesg -w
> ...
> usb 5-2.3.7: New USB device found, idVendor=0525, idProduct=a4a5, bcdDevice=7e.a7
> usb 5-2.3.7: New USB device strings: Mfr=1, Product=2, SerialNumber=3
> usb 5-2.3.7: Product: USB download gadget
> usb 5-2.3.7: Manufacturer: Vendor
> usb 5-2.3.7: SerialNumber: 1234abcd <--------------------------- HERE
> usb-storage 5-2.3.7:1.0: USB Mass Storage device detected
> ...
>
> $ lsusb -vd 0525:a4a5
>
> Bus 005 Device 052: ID 0525:a4a5 Netchip Technology, Inc. Linux-USB File-backed Storage Gadget
> Negotiated speed: High Speed (480Mbps)
> Device Descriptor:
> bLength 18
> bDescriptorType 1
> bcdUSB 2.00
> bDeviceClass 0 [unknown]
> bDeviceSubClass 0 [unknown]
> bDeviceProtocol 0
> bMaxPacketSize0 64
> idVendor 0x0525 Netchip Technology, Inc.
> idProduct 0xa4a5 Linux-USB File-backed Storage Gadget
> bcdDevice 7e.a7
> iManufacturer 1 Vendor
> iProduct 2 USB download gadget
> iSerial 3 1234abcd <-------------------------- HERE
> ...
> "
>
> Signed-off-by: Marek Vasut <marex@nabladev.com>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@kernel.org>
> ---
prev parent reply other threads:[~2026-06-15 7:18 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-13 2:54 [PATCH] cmd: ums: Set Device Descriptor iSerial based on serial# env variable Marek Vasut
2026-06-14 10:15 ` Łukasz Majewski
2026-06-15 7:18 ` Mattijs Korpershoek [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=875x3ki85f.fsf@kernel.org \
--to=mkorpershoek@kernel.org \
--cc=lukma@nabladev.com \
--cc=marex@nabladev.com \
--cc=sjg@chromium.org \
--cc=trini@konsulko.com \
--cc=u-boot@lists.denx.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox