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Alan Stern fb6f076d54 USB: hub: Add Kconfig option to reduce number of port initialization retries
Description based on one by Yasushi Asano:

According to 6.7.22 A-UUT “Device No Response” for connection timeout
of USB OTG and EH automated compliance plan v1.2, enumeration failure
has to be detected within 30 seconds.  However, the old and new
enumeration schemes each make a total of 12 attempts, and each attempt
can take 5 seconds to time out, so the PET test fails.

This patch adds a new Kconfig option (CONFIG_USB_FEW_INIT_RETRIES);
when the option is set all the initialization retry loops except the
outermost are reduced to a single iteration.  This reduces the total
number of attempts to four, allowing Linux hosts to pass the PET test.

The new option is disabled by default to preserve the existing
behavior.  The reduced number of retries may fail to initialize a few
devices that currently do work, but for the most part there should be
no change.  And in cases where the initialization does fail, it will
fail much more quickly.

Reported-and-tested-by: yasushi asano <yazzep@gmail.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20200928152217.GB134701@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-02 11:29:02 +02:00
arch Merge 5.0-rc6 into usb-next 2020-09-21 09:06:42 +02:00
block
certs
crypto
Documentation dt-bindings: usb: renesas,usbhs: Add r8a774e1 support 2020-09-22 10:38:47 +02:00
drivers USB: hub: Add Kconfig option to reduce number of port initialization retries 2020-10-02 11:29:02 +02:00
fs
include USB: correct API of usb_control_msg_send/recv 2020-09-25 16:33:58 +02:00
init
ipc
kernel Fix the seccomp syscall rewriting so that trace and audit see the 2020-09-20 15:37:15 -07:00
lib
LICENSES
mm
net
samples
scripts
security
sound sound: hiface: move to use usb_control_msg_send() 2020-09-25 16:33:59 +02:00
tools Fix noreturn detection for ignored sibling functions, from Josh 2020-09-20 15:31:04 -07:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Merge 5.0-rc6 into usb-next 2020-09-21 09:06:42 +02:00
Makefile Linux 5.9-rc6 2020-09-20 16:33:55 -07:00
README

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.