# # USB Host Controller Drivers # comment "USB Host Controller Drivers" config USB_C67X00_HCD tristate "Cypress C67x00 HCD support" help The Cypress C67x00 (EZ-Host/EZ-OTG) chips are dual-role host/peripheral/OTG USB controllers. Enable this option to support this chip in host controller mode. If unsure, say N. To compile this driver as a module, choose M here: the module will be called c67x00. config USB_XHCI_HCD tristate "xHCI HCD (USB 3.0) support" ---help--- The eXtensible Host Controller Interface (xHCI) is standard for USB 3.0 "SuperSpeed" host controller hardware. To compile this driver as a module, choose M here: the module will be called xhci-hcd. if USB_XHCI_HCD config USB_XHCI_PCI tristate depends on PCI default y config USB_XHCI_PLATFORM tristate prompt "xHCI platform support" if BCM_KF_USB_HOSTS config USB_XHCI_MVEBU tristate "xHCI support for Marvell Armada 375/38x" select USB_XHCI_PLATFORM depends on ARCH_MVEBU || COMPILE_TEST ---help--- Say 'Y' to enable the support for the xHCI host controller found in Marvell Armada 375/38x ARM SOCs. config USB_XHCI_RCAR tristate "xHCI support for Renesas R-Car SoCs" select USB_XHCI_PLATFORM depends on ARCH_SHMOBILE || COMPILE_TEST ---help--- Say 'Y' to enable the support for the xHCI host controller found in Renesas R-Car ARM SoCs. endif # USB_XHCI_HCD config USB_EHCI_HCD tristate "EHCI HCD (USB 2.0) support" ---help--- The Enhanced Host Controller Interface (EHCI) is standard for USB 2.0 "high speed" (480 Mbit/sec, 60 Mbyte/sec) host controller hardware. If your USB host controller supports USB 2.0, you will likely want to configure this Host Controller Driver. EHCI controllers are packaged with "companion" host controllers (OHCI or UHCI) to handle USB 1.1 devices connected to root hub ports. Ports will connect to EHCI if the device is high speed, otherwise they connect to a companion controller. If you configure EHCI, you should probably configure the OHCI (for NEC and some other vendors) USB Host Controller Driver or UHCI (for Via motherboards) Host Controller Driver too. You may want to read . To compile this driver as a module, choose M here: the module will be called ehci-hcd. config USB_EHCI_ROOT_HUB_TT bool "Root Hub Transaction Translators" depends on USB_EHCI_HCD ---help--- Some EHCI chips have vendor-specific extensions to integrate transaction translators, so that no OHCI or UHCI companion controller is needed. It's safe to say "y" even if your controller doesn't support this feature. This supports the EHCI implementation that's originally from ARC, and has since changed hands a few times. config USB_EHCI_TT_NEWSCHED bool "Improved Transaction Translator scheduling" depends on USB_EHCI_HCD default y ---help--- This changes the periodic scheduling code to fill more of the low and full speed bandwidth available from the Transaction Translator (TT) in USB 2.0 hubs. Without this, only one transfer will be issued in each microframe, significantly reducing the number of periodic low/fullspeed transfers possible. If you have multiple periodic low/fullspeed devices connected to a highspeed USB hub which is connected to a highspeed USB Host Controller, and some of those devices will not work correctly (possibly due to "ENOSPC" or "-28" errors), say Y. Conversely, if you have only one such device and it doesn't work, you could try saying N. If unsure, say Y. config USB_FSL_MPH_DR_OF tristate if USB_EHCI_HCD config USB_EHCI_PCI tristate depends on PCI default y config USB_EHCI_HCD_PMC_MSP tristate "EHCI support for on-chip PMC MSP71xx USB controller" depends on MSP_HAS_USB default n select USB_EHCI_BIG_ENDIAN_DESC select USB_EHCI_BIG_ENDIAN_MMIO ---help--- Enables support for the onchip USB controller on the PMC_MSP7100 Family SoC's. If unsure, say N. config XPS_USB_HCD_XILINX bool "Use Xilinx usb host EHCI controller core" depends on (PPC32 || MICROBLAZE) select USB_EHCI_BIG_ENDIAN_DESC select USB_EHCI_BIG_ENDIAN_MMIO ---help--- Xilinx xps USB host controller core is EHCI compliant and has transaction translator built-in. It can be configured to either support both high speed and full speed devices, or high speed devices only. config USB_EHCI_FSL bool "Support for Freescale PPC on-chip EHCI USB controller" depends on FSL_SOC select USB_EHCI_ROOT_HUB_TT select USB_FSL_MPH_DR_OF if OF ---help--- Variation of ARC USB block used in some Freescale chips. config USB_EHCI_MXC tristate "Support for Freescale i.MX on-chip EHCI USB controller" depends on ARCH_MXC select USB_EHCI_ROOT_HUB_TT ---help--- Variation of ARC USB block used in some Freescale chips. config USB_EHCI_HCD_OMAP tristate "EHCI support for OMAP3 and later chips" depends on ARCH_OMAP select NOP_USB_XCEIV default y ---help--- Enables support for the on-chip EHCI controller on OMAP3 and later chips. config USB_EHCI_HCD_ORION tristate "Support for Marvell EBU on-chip EHCI USB controller" depends on USB_EHCI_HCD && PLAT_ORION default y ---help--- Enables support for the on-chip EHCI controller on Marvell's embedded ARM SoCs, including Orion, Kirkwood, Dove, Armada XP, Armada 370. This is different from the EHCI implementation on Marvell's mobile PXA and MMP SoC, see "EHCI support for Marvell PXA/MMP USB controller" for those. config USB_EHCI_HCD_SPEAR tristate "Support for ST SPEAr on-chip EHCI USB controller" depends on USB_EHCI_HCD && PLAT_SPEAR default y ---help--- Enables support for the on-chip EHCI controller on ST SPEAr chips. config USB_EHCI_HCD_STI tristate "Support for ST STiHxxx on-chip EHCI USB controller" depends on ARCH_STI && OF select GENERIC_PHY select USB_EHCI_HCD_PLATFORM help Enable support for the on-chip EHCI controller found on STMicroelectronics consumer electronics SoC's. config USB_EHCI_HCD_AT91 tristate "Support for Atmel on-chip EHCI USB controller" depends on USB_EHCI_HCD && ARCH_AT91 default y ---help--- Enables support for the on-chip EHCI controller on Atmel chips. config USB_EHCI_MSM tristate "Support for Qualcomm QSD/MSM on-chip EHCI USB controller" depends on ARCH_QCOM select USB_EHCI_ROOT_HUB_TT ---help--- Enables support for the USB Host controller present on the Qualcomm chipsets. Root Hub has inbuilt TT. This driver depends on OTG driver for PHY initialization, clock management, powering up VBUS, and power management. This driver is not supported on boards like trout which has an external PHY. config USB_EHCI_TEGRA tristate "NVIDIA Tegra HCD support" depends on ARCH_TEGRA select USB_EHCI_ROOT_HUB_TT select USB_PHY help This driver enables support for the internal USB Host Controllers found in NVIDIA Tegra SoCs. The controllers are EHCI compliant. config USB_EHCI_HCD_PPC_OF bool "EHCI support for PPC USB controller on OF platform bus" depends on PPC default y ---help--- Enables support for the USB controller present on the PowerPC OpenFirmware platform bus. config USB_EHCI_SH bool "EHCI support for SuperH USB controller" depends on SUPERH ---help--- Enables support for the on-chip EHCI controller on the SuperH. If you use the PCI EHCI controller, this option is not necessary. config USB_EHCI_EXYNOS tristate "EHCI support for Samsung S5P/EXYNOS SoC Series" depends on ARCH_S5PV210 || ARCH_EXYNOS help Enable support for the Samsung Exynos SOC's on-chip EHCI controller. config USB_EHCI_MV bool "EHCI support for Marvell PXA/MMP USB controller" depends on (ARCH_PXA || ARCH_MMP) select USB_EHCI_ROOT_HUB_TT ---help--- Enables support for Marvell (including PXA and MMP series) on-chip USB SPH and OTG controller. SPH is a single port host, and it can only be EHCI host. OTG is controller that can switch to host mode. Note that this driver will not work on Marvell's other EHCI controller used by the EBU-type SoCs including Orion, Kirkwood, Dova, Armada 370 and Armada XP. See "Support for Marvell EBU on-chip EHCI USB controller" for those. config USB_W90X900_EHCI tristate "W90X900(W90P910) EHCI support" depends on ARCH_W90X900 ---help--- Enables support for the W90X900 USB controller config USB_CNS3XXX_EHCI bool "Cavium CNS3XXX EHCI Module (DEPRECATED)" depends on ARCH_CNS3XXX select USB_EHCI_HCD_PLATFORM ---help--- This option is deprecated now and the driver was removed, use USB_EHCI_HCD_PLATFORM instead. Enable support for the CNS3XXX SOC's on-chip EHCI controller. It is needed for high-speed (480Mbit/sec) USB 2.0 device support. config USB_EHCI_ATH79 bool "EHCI support for AR7XXX/AR9XXX SoCs (DEPRECATED)" depends on (SOC_AR71XX || SOC_AR724X || SOC_AR913X || SOC_AR933X) select USB_EHCI_ROOT_HUB_TT select USB_EHCI_HCD_PLATFORM default y ---help--- This option is deprecated now and the driver was removed, use USB_EHCI_HCD_PLATFORM instead. Enables support for the built-in EHCI controller present on the Atheros AR7XXX/AR9XXX SoCs. config USB_EHCI_HCD_PLATFORM tristate "Generic EHCI driver for a platform device" default n ---help--- Adds an EHCI host driver for a generic platform device, which provides a memory space and an irq. If unsure, say N. config USB_OCTEON_EHCI bool "Octeon on-chip EHCI support (DEPRECATED)" depends on CAVIUM_OCTEON_SOC default n select USB_EHCI_BIG_ENDIAN_MMIO select USB_EHCI_HCD_PLATFORM help This option is deprecated now and the driver was removed, use USB_EHCI_HCD_PLATFORM instead. Enable support for the Octeon II SOC's on-chip EHCI controller. It is needed for high-speed (480Mbit/sec) USB 2.0 device support. All CN6XXX based chips with USB are supported. endif # USB_EHCI_HCD config USB_OXU210HP_HCD tristate "OXU210HP HCD support" ---help--- The OXU210HP is an USB host/OTG/device controller. Enable this option if your board has this chip. If unsure, say N. This driver does not support isochronous transfers and doesn't implement OTG nor USB device controllers. To compile this driver as a module, choose M here: the module will be called oxu210hp-hcd. config USB_ISP116X_HCD tristate "ISP116X HCD support" ---help--- The ISP1160 and ISP1161 chips are USB host controllers. Enable this option if your board has this chip. If unsure, say N. This driver does not support isochronous transfers. To compile this driver as a module, choose M here: the module will be called isp116x-hcd. config USB_ISP1362_HCD tristate "ISP1362 HCD support" ---help--- Supports the Philips ISP1362 chip as a host controller This driver does not support isochronous transfers. To compile this driver as a module, choose M here: the module will be called isp1362-hcd. config USB_FUSBH200_HCD tristate "FUSBH200 HCD support" depends on USB ---help--- Faraday FUSBH200 is designed to meet USB2.0 EHCI specification with minor modification. To compile this driver as a module, choose M here: the module will be called fusbh200-hcd. config USB_FOTG210_HCD tristate "FOTG210 HCD support" depends on USB ---help--- Faraday FOTG210 is an OTG controller which can be configured as an USB2.0 host. It is designed to meet USB2.0 EHCI specification with minor modification. To compile this driver as a module, choose M here: the module will be called fotg210-hcd. config USB_MAX3421_HCD tristate "MAX3421 HCD (USB-over-SPI) support" depends on USB && SPI ---help--- The Maxim MAX3421E chip supports standard USB 2.0-compliant full-speed devices either in host or peripheral mode. This driver supports the host-mode of the MAX3421E only. To compile this driver as a module, choose M here: the module will be called max3421-hcd. config USB_OHCI_HCD tristate "OHCI HCD (USB 1.1) support" ---help--- The Open Host Controller Interface (OHCI) is a standard for accessing USB 1.1 host controller hardware. It does more in hardware than Intel's UHCI specification. If your USB host controller follows the OHCI spec, say Y. On most non-x86 systems, and on x86 hardware that's not using a USB controller from Intel or VIA, this is appropriate. If your host controller doesn't use PCI, this is probably appropriate. For a PCI based system where you're not sure, the "lspci -v" entry will list the right "prog-if" for your USB controller(s): EHCI, OHCI, or UHCI. To compile this driver as a module, choose M here: the module will be called ohci-hcd. if USB_OHCI_HCD config USB_OHCI_HCD_OMAP1 tristate "OHCI support for OMAP1/2 chips" depends on ARCH_OMAP1 depends on ISP1301_OMAP || !(MACH_OMAP_H2 || MACH_OMAP_H3) default y ---help--- Enables support for the OHCI controller on OMAP1/2 chips. config USB_OHCI_HCD_SPEAR tristate "Support for ST SPEAr on-chip OHCI USB controller" depends on USB_OHCI_HCD && PLAT_SPEAR default y ---help--- Enables support for the on-chip OHCI controller on ST SPEAr chips. config USB_OHCI_HCD_STI tristate "Support for ST STiHxxx on-chip OHCI USB controller" depends on ARCH_STI && OF select GENERIC_PHY select USB_OHCI_HCD_PLATFORM help Enable support for the on-chip OHCI controller found on STMicroelectronics consumer electronics SoC's. config USB_OHCI_HCD_S3C2410 tristate "OHCI support for Samsung S3C24xx/S3C64xx SoC series" depends on USB_OHCI_HCD && (ARCH_S3C24XX || ARCH_S3C64XX) default y ---help--- Enables support for the on-chip OHCI controller on S3C24xx/S3C64xx chips. config USB_OHCI_HCD_LPC32XX tristate "Support for LPC on-chip OHCI USB controller" depends on USB_OHCI_HCD && ARCH_LPC32XX depends on USB_ISP1301 default y ---help--- Enables support for the on-chip OHCI controller on NXP chips. config USB_OHCI_HCD_PXA27X tristate "Support for PXA27X/PXA3XX on-chip OHCI USB controller" depends on USB_OHCI_HCD && (PXA27x || PXA3xx) default y ---help--- Enables support for the on-chip OHCI controller on PXA27x/PXA3xx chips. config USB_OHCI_HCD_AT91 tristate "Support for Atmel on-chip OHCI USB controller" depends on USB_OHCI_HCD && ARCH_AT91 default y ---help--- Enables support for the on-chip OHCI controller on Atmel chips. config USB_OHCI_HCD_OMAP3 tristate "OHCI support for OMAP3 and later chips" depends on (ARCH_OMAP3 || ARCH_OMAP4) default y ---help--- Enables support for the on-chip OHCI controller on OMAP3 and later chips. config USB_OHCI_HCD_DAVINCI bool "OHCI support for TI DaVinci DA8xx" depends on ARCH_DAVINCI_DA8XX depends on USB_OHCI_HCD=y default y help Enables support for the DaVinci DA8xx integrated OHCI controller. This driver cannot currently be a loadable module because it lacks a proper PHY abstraction. config USB_OHCI_ATH79 bool "USB OHCI support for the Atheros AR71XX/AR7240 SoCs (DEPRECATED)" depends on (SOC_AR71XX || SOC_AR724X) select USB_OHCI_HCD_PLATFORM default y help This option is deprecated now and the driver was removed, use USB_OHCI_HCD_PLATFORM instead. Enables support for the built-in OHCI controller present on the Atheros AR71XX/AR7240 SoCs. config USB_OHCI_HCD_PPC_OF_BE bool "OHCI support for OF platform bus (big endian)" depends on PPC select USB_OHCI_BIG_ENDIAN_DESC select USB_OHCI_BIG_ENDIAN_MMIO ---help--- Enables support for big-endian USB controllers present on the OpenFirmware platform bus. config USB_OHCI_HCD_PPC_OF_LE bool "OHCI support for OF platform bus (little endian)" depends on PPC select USB_OHCI_LITTLE_ENDIAN ---help--- Enables support for little-endian USB controllers present on the OpenFirmware platform bus. config USB_OHCI_HCD_PPC_OF bool depends on PPC default USB_OHCI_HCD_PPC_OF_BE || USB_OHCI_HCD_PPC_OF_LE config USB_OHCI_HCD_PCI tristate "OHCI support for PCI-bus USB controllers" depends on PCI default y select USB_OHCI_LITTLE_ENDIAN ---help--- Enables support for PCI-bus plug-in USB controller cards. If unsure, say Y. config USB_OHCI_HCD_SSB bool "OHCI support for Broadcom SSB OHCI core (DEPRECATED)" depends on (SSB = y || SSB = USB_OHCI_HCD) select USB_HCD_SSB select USB_OHCI_HCD_PLATFORM default n ---help--- This option is deprecated now and the driver was removed, use USB_HCD_SSB and USB_OHCI_HCD_PLATFORM instead. Support for the Sonics Silicon Backplane (SSB) attached Broadcom USB OHCI core. This device is present in some embedded devices with Broadcom based SSB bus. If unsure, say N. config USB_OHCI_SH bool "OHCI support for SuperH USB controller (DEPRECATED)" depends on SUPERH select USB_OHCI_HCD_PLATFORM ---help--- This option is deprecated now and the driver was removed, use USB_OHCI_HCD_PLATFORM instead. Enables support for the on-chip OHCI controller on the SuperH. If you use the PCI OHCI controller, this option is not necessary. config USB_OHCI_EXYNOS tristate "OHCI support for Samsung S5P/EXYNOS SoC Series" depends on ARCH_S5PV210 || ARCH_EXYNOS help Enable support for the Samsung Exynos SOC's on-chip OHCI controller. config USB_CNS3XXX_OHCI bool "Cavium CNS3XXX OHCI Module (DEPRECATED)" depends on ARCH_CNS3XXX select USB_OHCI_HCD_PLATFORM ---help--- This option is deprecated now and the driver was removed, use USB_OHCI_HCD_PLATFORM instead. Enable support for the CNS3XXX SOC's on-chip OHCI controller. It is needed for low-speed USB 1.0 device support. config USB_OHCI_HCD_PLATFORM tristate "Generic OHCI driver for a platform device" default n ---help--- Adds an OHCI host driver for a generic platform device, which provides a memory space and an irq. If unsure, say N. config USB_OCTEON_OHCI bool "Octeon on-chip OHCI support (DEPRECATED)" depends on CAVIUM_OCTEON_SOC default USB_OCTEON_EHCI select USB_OHCI_BIG_ENDIAN_MMIO select USB_OHCI_LITTLE_ENDIAN select USB_OHCI_HCD_PLATFORM help This option is deprecated now and the driver was removed, use USB_OHCI_HCD_PLATFORM instead. Enable support for the Octeon II SOC's on-chip OHCI controller. It is needed for low-speed USB 1.0 device support. All CN6XXX based chips with USB are supported. endif # USB_OHCI_HCD config USB_UHCI_HCD tristate "UHCI HCD (most Intel and VIA) support" depends on PCI || USB_UHCI_SUPPORT_NON_PCI_HC ---help--- The Universal Host Controller Interface is a standard by Intel for accessing the USB hardware in the PC (which is also called the USB host controller). If your USB host controller conforms to this standard, you may want to say Y, but see below. All recent boards with Intel PCI chipsets (like intel 430TX, 440FX, 440LX, 440BX, i810, i820) conform to this standard. Also all VIA PCI chipsets (like VIA VP2, VP3, MVP3, Apollo Pro, Apollo Pro II or Apollo Pro 133) and LEON/GRLIB SoCs with the GRUSBHC controller. If unsure, say Y. To compile this driver as a module, choose M here: the module will be called uhci-hcd. config USB_UHCI_SUPPORT_NON_PCI_HC bool default y if (SPARC_LEON || USB_UHCI_PLATFORM) config USB_UHCI_PLATFORM bool default y if ARCH_VT8500 config USB_UHCI_BIG_ENDIAN_MMIO bool default y if SPARC_LEON config USB_UHCI_BIG_ENDIAN_DESC bool default y if SPARC_LEON config USB_FHCI_HCD tristate "Freescale QE USB Host Controller support" depends on OF_GPIO && QE_GPIO && QUICC_ENGINE select FSL_GTM select QE_USB help This driver enables support for Freescale QE USB Host Controller (as found on MPC8360 and MPC8323 processors), the driver supports Full and Low Speed USB. config FHCI_DEBUG bool "Freescale QE USB Host Controller debug support" depends on USB_FHCI_HCD && DEBUG_FS help Say "y" to see some FHCI debug information and statistics through debugfs. config USB_U132_HCD tristate "Elan U132 Adapter Host Controller" depends on USB_FTDI_ELAN help The U132 adapter is a USB to CardBus adapter specifically designed for PC cards that contain an OHCI host controller. Typical PC cards are the Orange Mobile 3G Option GlobeTrotter Fusion card. The U132 adapter will *NOT* work with PC cards that do not contain an OHCI controller. For those PC cards that contain multiple OHCI controllers only the first one is used. The driver consists of two modules, the "ftdi-elan" module is a USB client driver that interfaces to the FTDI chip within ELAN's USB-to-PCMCIA adapter, and this "u132-hcd" module is a USB host controller driver that talks to the OHCI controller within the CardBus cards that are inserted in the U132 adapter. This driver has been tested with a CardBus OHCI USB adapter, and worked with a USB PEN Drive inserted into the first USB port of the PCCARD. A rather pointless thing to do, but useful for testing. It is safe to say M here. See also config USB_SL811_HCD tristate "SL811HS HCD support" help The SL811HS is a single-port USB controller that supports either host side or peripheral side roles. Enable this option if your board has this chip, and you want to use it as a host controller. If unsure, say N. To compile this driver as a module, choose M here: the module will be called sl811-hcd. config USB_SL811_HCD_ISO bool "partial ISO support" depends on USB_SL811_HCD help The driver doesn't support iso_frame_desc (yet), but for some simple devices that just queue one ISO frame per URB, then ISO transfers "should" work using the normal urb status fields. If unsure, say N. config USB_SL811_CS tristate "CF/PCMCIA support for SL811HS HCD" depends on USB_SL811_HCD && PCMCIA help Wraps a PCMCIA driver around the SL811HS HCD, supporting the RATOC REX-CFU1U CF card (often used with PDAs). If unsure, say N. To compile this driver as a module, choose M here: the module will be called "sl811_cs". config USB_R8A66597_HCD tristate "R8A66597 HCD support" help The R8A66597 is a USB 2.0 host and peripheral controller. Enable this option if your board has this chip, and you want to use it as a host controller. If unsure, say N. To compile this driver as a module, choose M here: the module will be called r8a66597-hcd. config USB_RENESAS_USBHS_HCD tristate "Renesas USBHS HCD support" depends on USB_RENESAS_USBHS help The Renesas USBHS is a USB 2.0 host and peripheral controller. Enable this option if your board has this chip, and you want to use it as a host controller. If unsure, say N. To compile this driver as a module, choose M here: the module will be called renesas-usbhs. config USB_WHCI_HCD tristate "Wireless USB Host Controller Interface (WHCI) driver" depends on PCI && USB && UWB select USB_WUSB select UWB_WHCI help A driver for PCI-based Wireless USB Host Controllers that are compliant with the WHCI specification. To compile this driver a module, choose M here: the module will be called "whci-hcd". config USB_HWA_HCD tristate "Host Wire Adapter (HWA) driver" depends on USB && UWB select USB_WUSB select UWB_HWA help This driver enables you to connect Wireless USB devices to your system using a Host Wire Adaptor USB dongle. This is an UWB Radio Controller and WUSB Host Controller connected to your machine via USB (specified in WUSB1.0). To compile this driver a module, choose M here: the module will be called "hwa-hc". config USB_IMX21_HCD tristate "i.MX21 HCD support" depends on ARM && ARCH_MXC help This driver enables support for the on-chip USB host in the i.MX21 processor. To compile this driver as a module, choose M here: the module will be called "imx21-hcd". config USB_HCD_BCMA tristate "BCMA usb host driver" depends on BCMA select USB_OHCI_HCD_PLATFORM if USB_OHCI_HCD select USB_EHCI_HCD_PLATFORM if USB_EHCI_HCD help Enable support for the EHCI and OCHI host controller on an bcma bus. It converts the bcma driver into two platform device drivers for ehci and ohci. If unsure, say N. config USB_HCD_SSB tristate "SSB usb host driver" depends on SSB select USB_OHCI_HCD_PLATFORM if USB_OHCI_HCD select USB_EHCI_HCD_PLATFORM if USB_EHCI_HCD help Enable support for the EHCI and OCHI host controller on an bcma bus. It converts the bcma driver into two platform device drivers for ehci and ohci. If unsure, say N. config USB_HCD_TEST_MODE bool "HCD test mode support" ---help--- Say 'Y' to enable additional software test modes that may be supported by the host controller drivers. One such test mode is the Embedded High-speed Host Electrical Test (EHSET) for EHCI host controller hardware, specifically the "Single Step Set Feature" test. Typically this will be enabled for On-the-Go or embedded hosts that need to undergo USB-IF compliance testing with the aid of special testing hardware. In the future, this may expand to include other tests that require support from a HCD driver. This option is of interest only to developers who need to validate their USB hardware designs. It is not needed for normal use. If unsure, say N.