spec violation of xHCI?

[Kohji Okuno]

Hi,

I think the xHCI host controller driver has a spec violation.

Could you refer to 
``Table 126: Offset 0Ch – Link TRB Field Definitions''
in  xHCI_Specification_for_USB.pdf(Revision 1.0)?

The following is an excerpt about the CHAIN ​​BIT.

  Chain bit (CH). Set to ‘1’ by software to associate this TRB with
  the next TRB on the Ring. A Transfer Descriptor (TD) is defined as
  one or more TRBs. The Chain bit is used to identify the TRBs that
  comprise a TD. Refer to section 4.11.7 for more information on Link
  TRB placement within a TD. On a Command Ring this bit is ignored by
  the xHC.


I think that we should add XHCI_TRB_3_CHAIN_BIT to line 1895.
How do you think?


src/sys/dev/usb/controller/xhci.c:
1879	                /* fill out link TRB */
1880	
1881	                if (td_next != NULL) {
1882	                        /* link the current TD with the next one */
1883	                        td->td_trb[x].qwTrb0 = htole64((uint64_t)td_next->td_self);
1884	                        DPRINTF("LINK=0x%08llx\n", (long long)td_next->td_self);
1885	                } else {
1886	                        /* this field will get updated later */
1887	                        DPRINTF("NOLINK\n");
1888	                }
1889	
1890	                dword = XHCI_TRB_2_IRQ_SET(0);
1891	
1892	                td->td_trb[x].dwTrb2 = htole32(dword);
1893	
1894	                dword = XHCI_TRB_3_TYPE_SET(XHCI_TRB_TYPE_LINK) |
1895	                    XHCI_TRB_3_CYCLE_BIT | XHCI_TRB_3_IOC_BIT;
1896	
1897	                td->td_trb[x].dwTrb3 = htole32(dword);
1898	
1899	                td->alt_next = td_alt_next;

--
Best regards,
 Kohji Okuno