Commit c749f058 authored by Kannappan R's avatar Kannappan R Committed by Greg Kroah-Hartman
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USB: core: Add eUSB2 descriptor and parsing in USB core



Add support for the 'eUSB2 Isochronous Endpoint Companion Descriptor'
introduced in the recent USB 2.0 specification 'USB 2.0 Double Isochronous
IN Bandwidth' ECN.

It allows embedded USB2 (eUSB2) devices to report and use higher bandwidths
for isochronous IN transfers in order to support higher camera resolutions
on the lid of laptops and tablets with minimal change to the USB2 protocol.

The motivation for expanding USB 2.0 is further clarified in an additional
Embedded USB2 version 2.0 (eUSB2v2) supplement to the USB 2.0
specification. It points out this is optimized for performance, power and
cost by using the USB 2.0 low-voltage, power efficient PHY and half-duplex
link for the asymmetric camera bandwidth needs, avoiding the costly and
complex full-duplex USB 3.x symmetric link and gigabit receivers.

eUSB2 devices that support the higher isochronous IN bandwidth and the new
descriptor can be identified by their device descriptor bcdUSB value of
0x0220

Co-developed-by: default avatarAmardeep Rai <amardeep.rai@intel.com>
Signed-off-by: default avatarAmardeep Rai <amardeep.rai@intel.com>
Signed-off-by: default avatarKannappan R <r.kannappan@intel.com>
Co-developed-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20250220141339.1939448-1-mathias.nyman@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 0a86e49a
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