On Wed, Feb 08, 2017 at 02:44:44PM +0100, Alexander Stein wrote: > This patch adds support for USB2 test mode (Test_J, Test_K, > Test_SE0_NAK and Test_Packet) per XHCI spec 4.19.6. > > USB2 test mode is a required hardware feature for system integrators > validating their hardware according to USB spec, regarding signal > strength and stuff. It is purely a hardware test feature. > > Usually you need an oscilloscope and have to enable those test modes on > the hardware. This will send some specific test patterns on D+/D-. There > is no report available (in Linux itself) as it is purely externally > visible. Regular USB usage is not possible at that time. > Anyone (well access to e.g. /dev/bus/usb/001/001 provided) can use it by > sending appropriate USB_PORT_FEAT_TEST requests to the hub. > The same feature for ehci based hosts is already available at > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/usb/host/ehci-hub.c#n1267 > > Signed-off-by: "Wang, Yu" <yu.y.wang@xxxxxxxxx> > Signed-off-by: "Li, Guanglei" <guangleix.li@xxxxxxxxx> > Signed-off-by: "Wu, Hao" <hao.wu@xxxxxxxxx> > Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxxxxxxxx> > --- > Changes in v2: > * Added additional info about USB2 test modes itself into commit message > * Add URL for same test mode feature on ehci hosts. Much nicer, thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
