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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>
119 lines
4.3 KiB
Plaintext
119 lines
4.3 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0
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#
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# USB Core configuration
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#
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config USB_ANNOUNCE_NEW_DEVICES
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bool "USB announce new devices"
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help
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Say Y here if you want the USB core to always announce the
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idVendor, idProduct, Manufacturer, Product, and SerialNumber
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strings for every new USB device to the syslog. This option is
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usually used by distro vendors to help with debugging and to
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let users know what specific device was added to the machine
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in what location.
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If you do not want this kind of information sent to the system
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log, or have any doubts about this, say N here.
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comment "Miscellaneous USB options"
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config USB_DEFAULT_PERSIST
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bool "Enable USB persist by default"
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default y
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help
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Say N here if you don't want USB power session persistence
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enabled by default. If you say N it will make suspended USB
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devices that lose power get reenumerated as if they had been
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unplugged, causing any mounted filesystems to be lost. The
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persist feature can still be enabled for individual devices
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through the power/persist sysfs node. See
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Documentation/driver-api/usb/persist.rst for more info.
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If you have any questions about this, say Y here, only say N
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if you know exactly what you are doing.
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config USB_FEW_INIT_RETRIES
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bool "Limit USB device initialization to only a few retries"
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help
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When a new USB device is detected, the kernel tries very hard
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to initialize and enumerate it, with lots of nested retry loops.
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This almost always works, but when it fails it can take a long time.
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This option tells the kernel to make only a few retry attempts,
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so that the total time required for a failed initialization is
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no more than 30 seconds (as required by the USB OTG spec).
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Say N here unless you require new-device enumeration failure to
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occur within 30 seconds (as might be needed in an embedded
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application).
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config USB_DYNAMIC_MINORS
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bool "Dynamic USB minor allocation"
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help
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If you say Y here, the USB subsystem will use dynamic minor
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allocation for any device that uses the USB major number.
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This means that you can have more than 16 of a single type
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of device (like USB printers).
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If you are unsure about this, say N here.
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config USB_OTG
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bool "OTG support"
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depends on PM
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help
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The most notable feature of USB OTG is support for a
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"Dual-Role" device, which can act as either a device
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or a host. The initial role is decided by the type of
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plug inserted and can be changed later when two dual
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role devices talk to each other.
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Select this only if your board has Mini-AB/Micro-AB
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connector.
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config USB_OTG_PRODUCTLIST
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bool "Rely on OTG and EH Targeted Peripherals List"
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depends on USB
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help
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If you say Y here, the "otg_productlist.h" file will be used as a
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product list, so USB peripherals not listed there will be
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rejected during enumeration. This behavior is required by the
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USB OTG and EH specification for all devices not on your product's
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"Targeted Peripherals List". "Embedded Hosts" are likewise
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allowed to support only a limited number of peripherals.
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config USB_OTG_DISABLE_EXTERNAL_HUB
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bool "Disable external hubs"
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depends on USB_OTG || EXPERT
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help
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If you say Y here, then Linux will refuse to enumerate
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external hubs. OTG hosts are allowed to reduce hardware
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and software costs by not supporting external hubs. So
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are "Embedded Hosts" that don't offer OTG support.
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config USB_OTG_FSM
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tristate "USB 2.0 OTG FSM implementation"
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depends on USB && USB_OTG
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select USB_PHY
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help
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Implements OTG Finite State Machine as specified in On-The-Go
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and Embedded Host Supplement to the USB Revision 2.0 Specification.
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config USB_LEDS_TRIGGER_USBPORT
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tristate "USB port LED trigger"
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depends on USB && LEDS_TRIGGERS
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help
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This driver allows LEDs to be controlled by USB events. Enabling this
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trigger allows specifying list of USB ports that should turn on LED
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when some USB device gets connected.
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config USB_AUTOSUSPEND_DELAY
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int "Default autosuspend delay"
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depends on USB
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default 2
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help
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The default autosuspend delay in seconds. Can be overridden
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with the usbcore.autosuspend command line or module parameter.
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The default value Linux has always had is 2 seconds. Change
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this value if you want a different delay and cannot modify
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the command line or module parameter.
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