On Tue, Oct 25, 2016 at 12:32:41PM +0800, Lu Baolu wrote: > xHCI debug capability (DbC) is an optional but standalone > functionality provided by an xHCI host controller. With DbC > hardware initialized, the system will present a debug device > through the USB3 debug port (normally the first USB3 port). > The debug device is fully compliant with the USB framework > and provides the equivalent of a very high performance (USB3) > full-duplex serial link between the debug host and target. > The DbC functionality is independent of xHCI host. There > isn't any precondition from xHCI host side for DbC to work. > > This patch set adds support for early printk functionality > through a USB3 debug port by 1) initializing and enabling > the DbC hardware during early boot; 2) registering a boot > console to the system so that early printk messages can go > through the USB3 debug port. It also includes some lines > of changes in usb_debug driver so that it can be bound when > a USB3 debug device is enumerated. > > This code is designed to be used only for kernel debugging > when machine crashes very early before the console code is > initialized. It makes the life of kernel debugging easier > when people work with a modern machine without any legacy > serial ports. > > --- > Change log: > v2->v3: > - Removed spinlock usage. > - Removed work queue usage. > - Refined the user guide document. How is this a "RESEND" if this is the first time we have seen v3? confused, greg k-h -- 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
