Re: [PATCH] usb: xhci: Relax high-speed bulk max packet size rules

[sashiko-bot@kernel.org]

> Nicolai reported multiple dodgy high-speed devices still being made
> which declare out-of-spec bulk wMaxPacketSize and actually require
> the host to use it for correct operation. Apparently, Windows copies
> this field to the EP Context verbatim and other Linux HCDs like EHCI
> and DWC2 do similar things for compatibility's sake.
> 
> We are also aware of devices like astronomical cameras which use 1KB
> to reduce protocol overhead, and audio devices with MIDI endpoints
> that specify unusual MPS like 8 or 4 (the latter was full-speed) and
> work with larger sizes just fine because they never do multi-packet
> transfers where MPS really matters.
> 
> I found that sensible (power of two, 8 - 512) MPS are usable on many
> xHCI controllers from vendors like AMD, ASMedia, Fresco, NEC/Renesas,
> and VIA. Nicolai also tested two Raspberry Pi SBCs and a modern Intel
> [ ... ]
> Closes: https://lore.kernel.org/linux-usb/20261020-fix-usbtmc-short-packets-v1-0-903f4d029193@tipi-net.de/
> Link: https://lore.kernel.org/linux-usb/93d5aeb4-f1c7-9342-7bc5-4b277b4ec55e@veikia.lt/
> Link: https://lore.kernel.org/alsa-devel/CAE-xCyPhrS6pgY0T9SG0TCubSi0CE2Yd5H=ttOzBmvgrR8fTPA@mail.gmail.com/
> Link: https://lore.kernel.org/linux-usb/348c50de-f922-8295-ef87-cf5cdea5c7f4@gmail.com/
> Signed-off-by: Michal Pecio <michal.pecio@gmail.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261028104329.3d1c8029.michal.pecio@gmail.com?part=1