From: Michal Pecio <michal.pecio@gmail.com>
To: Jeffrey Hein <jp@jphein.com>
Cc: Ricardo Ribalda <ribalda@chromium.org>,
Alan Stern <stern@rowland.harvard.edu>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Hans de Goede <hansg@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-media@vger.kernel.org, linux-usb@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH v5 2/3] media: uvcvideo: add UVC_QUIRK_CTRL_THROTTLE for fragile firmware
Date: Fri, 10 Apr 2026 06:47:16 +0200 [thread overview]
Message-ID: <20260410064716.1f5d69c4.michal.pecio@gmail.com> (raw)
In-Reply-To: <CAD5VvzCVxn6ehen4vzbzJzm3Akc-0BREhMZrfsffXTz782jQcw@mail.gmail.com>
On Thu, 9 Apr 2026 17:24:36 -0700, Jeffrey Hein wrote:
> So wBytesPerInterval (8) is indeed 8x smaller than wMaxPacketSize
> (64), matching what you saw in the third-party listing.
Technically it's a spec violation if a device claims 8 bytes but
respons with a single packet larger than that to a 16 byte (or any
other) URB. Though no problems were known to result until last month.
It seems most host controllers ignore byte per interval on interrupt.
> Note that lsusb -vv does not decode wBytesPerInterval for this
> endpoint -- the value above was parsed from the raw descriptor bytes
> in sysfs. The full lsusb -vv (934 lines) is now in the repo:
It does decode it, but you need the latest usbutils version 019.
And there should be no need for lsusb -vv, just lsusb -v.
I think the output pasted into v6 patch was truncated.
Regards,
Michal
next prev parent reply other threads:[~2026-04-10 4:47 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20260331003806.212565-1-jp@jphein.com>
2026-03-31 0:38 ` [PATCH v5 1/3] USB: core: add NO_LPM quirk for Razer Kiyo Pro webcam JP Hein
2026-03-31 0:38 ` [PATCH v5 2/3] media: uvcvideo: add UVC_QUIRK_CTRL_THROTTLE for fragile firmware JP Hein
2026-04-09 6:45 ` Ricardo Ribalda
[not found] ` <CAD5VvzAu8+Qz7hEEBzuKvO11X=YD-wrtX3_Tk77g2Cq5rZZD0Q@mail.gmail.com>
2026-04-09 7:51 ` Jeffrey Hein
2026-04-09 8:02 ` Michal Pecio
2026-04-09 8:15 ` Jeffrey Hein
2026-04-09 20:17 ` Michal Pecio
2026-04-10 0:01 ` Jeffrey Hein
2026-04-10 0:24 ` Jeffrey Hein
2026-04-10 4:47 ` Michal Pecio [this message]
2026-03-31 0:38 ` [PATCH v5 3/3] media: uvcvideo: add quirks for Razer Kiyo Pro webcam JP Hein
2026-04-09 6:49 ` Ricardo Ribalda
2026-04-09 7:38 ` Jeffrey Hein
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