On Fri, Oct 05, 2012 at 10:34:19AM +0800, loody wrote: > hi Sarah: > > 2012/10/5 Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>: > > On Thu, Oct 04, 2012 at 01:47:44PM +0800, loody wrote: > >> Hi all: > >> from below out put slot context it shows ep0 consumer cycle bit is 1 > >> but why when we enqueue control transfer we purposely leave setup > >> status cycle bit as 0. > >> (below I purpose dump control trb content and 0xcf01c80c should be > >> 0x00000841 instead of 0x00000840, right?) > >> > >> [192016.504076] address trb: cf01c800: 01000680 00080000 00000008 00000840 > >> [192016.505593] address trb: cf01c810: 30e1fdc0 00000000 00000008 00010c05 > >> [192016.507129] address trb: cf01c820: 00000000 00000000 00000000 00001021 > > > > We leave the setup status cycle bit as zero until we've written the > > status phase to the ring. This is to prevent the host from executing > > the control transfer until it's fully written to the ring. We do the > > same thing for all transfer descriptors (TD) that have more than one > > transfer request buffer (TRB). > > > > BTW, if you're asking questions about the xHCI driver, you really should > > put me on Cc. Otherwise your mail might get lost in all the other > > linux-usb mail I get. > > > > Why are you asking all these questions about the driver? What are you > > trying to accomplish? > Nice to meet U ~^^~ > I am trying to port xhci driver on my platform based on linux driver. > That is why I ask these questions. I see. Is there a particular reason why the current Linux xHCI driver doesn't meet your needs? Like maybe your host isn't PCI based? I'm confused as to why you would need to understand the low-level details of ring management if you're doing a simple port. Sarah Sharp -- 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
