Hi Pratyush, The NumP=4 from the host probably means that the host only has buffer space for 4 1K packets. 4K is the page size, so maybe the host was given a scatter-gather list made up of single pages (just a guess). Or else the host system just cannot empty the buffers quick enough to keep up. What is the host OS and driver? We have found that the Linux xHCI driver does not perform very well compared to the MCCI xHCI driver under Windows (which AFAIK is the xHCI driver you usually get when you buy a NEC/Renesas host adapter). Did you get a Windows xHCI driver along with your TUSB7340 adapter? -- Paul -----Original Message----- From: linux-usb-owner@xxxxxxxxxxxxxxx [mailto:linux-usb-owner@xxxxxxxxxxxxxxx] On Behalf Of Pratyush Anand Sent: Wednesday, October 17, 2012 6:13 AM To: Sarah Sharp; Paul Zimmerman Cc: USB list; spear-devel Subject: Query: USB: XHCI: Endpoint Context Max Burst Capability Hi, I was trying to test max bulk through put capability of my usb3.0 device. Bulk IN EP Companion descriptor's bMaxburst is 15 in my gadget. My host controller is TUSB7340. I see, that Device Sends ERDY with NumP=16. Host sends ACK with NumP=4. I noticed that xhci driver programs Max Burst Size same as that of reported by companion descriptor. So, what does it mean, host controller's Max Burst is 4 only? So, even if driver programs 15, it is limited by 3. If yes, Does anybody know about any host controller supporting Max Burst as 16 on Bulk EP? Regards Pratyush -- 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
