3adcbec4dc
[ Upstream commit 5a1ccf0c72cf917ff3ccc131d1bb8d19338ffe52 ] This patch introduces a new USB quirk, USB_QUIRK_SHORT_SET_ADDRESS_REQ_TIMEOUT, which modifies the timeout value for the SET_ADDRESS request. The standard timeout for USB request/command is 5000 ms, as recommended in the USB 3.2 specification (section 9.2.6.1). However, certain scenarios, such as connecting devices through an APTIV hub, can lead to timeout errors when the device enumerates as full speed initially and later switches to high speed during chirp negotiation. In such cases, USB analyzer logs reveal that the bus suspends for 5 seconds due to incorrect chirp parsing and resumes only after two consecutive timeout errors trigger a hub driver reset. Packet(54) Dir(?) Full Speed J(997.100 us) Idle( 2.850 us) _______| Time Stamp(28 . 105 910 682) _______|_____________________________________________________________Ch0 Packet(55) Dir(?) Full Speed J(997.118 us) Idle( 2.850 us) _______| Time Stamp(28 . 106 910 632) _______|_____________________________________________________________Ch0 Packet(56) Dir(?) Full Speed J(399.650 us) Idle(222.582 us) _______| Time Stamp(28 . 107 910 600) _______|_____________________________________________________________Ch0 Packet(57) Dir Chirp J( 23.955 ms) Idle(115.169 ms) _______| Time Stamp(28 . 108 532 832) _______|_____________________________________________________________Ch0 Packet(58) Dir(?) Full Speed J (Suspend)( 5.347 sec) Idle( 5.366 us) _______| Time Stamp(28 . 247 657 600) _______|_____________________________________________________________Ch0 This 5-second delay in device enumeration is undesirable, particularly in automotive applications where quick enumeration is crucial (ideally within 3 seconds). The newly introduced quirks provide the flexibility to align with a 3-second time limit, as required in specific contexts like automotive applications. By reducing the SET_ADDRESS request timeout to 500 ms, the system can respond more swiftly to errors, initiate rapid recovery, and ensure efficient device enumeration. This change is vital for scenarios where rapid smartphone enumeration and screen projection are essential. To use the quirk, please write "vendor_id:product_id:p" to /sys/bus/usb/drivers/hub/module/parameter/quirks For example, echo "0x2c48:0x0132:p" > /sys/bus/usb/drivers/hub/module/parameters/quirks" Signed-off-by: Hardik Gajjar <hgajjar@de.adit-jv.com> Reviewed-by: Alan Stern <stern@rowland.harvard.edu> Link: https://lore.kernel.org/r/20231027152029.104363-2-hgajjar@de.adit-jv.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.