Hi Sarah, On Wed, Mar 20, 2013 at 10:17 AM, Vivek Gautam <gautamvivek1987@xxxxxxxxx> wrote: > Hi, > > > On Wed, Mar 20, 2013 at 12:51 AM, Sarah Sharp > <sarah.a.sharp@xxxxxxxxxxxxxxx> wrote: >> On Thu, Mar 07, 2013 at 03:38:46PM +0530, Vivek Gautam wrote: >>> Hi Sarah, >>> >>> >>> While going through the code for Handling Transfer Events >>> (drivers/usb/host/xhci-ring.c), i hit upon this problem. >>> As defined in "drivers/usb/host/xhci.h" >>> >>> /* Normal TRB fields */ >>> /* transfer_len bitmasks - bits 0:16 */ >>> #define TRB_LEN(p) ((p) & 0x1ffff) >>> >>> And the same macro i could see being used while Handling Trasfer >>> events "handle_tx_event()", and further in >>> process_ctrl_td(), process_isoc_td(), and process_bulk_intr_td(). >>> >>> However, as per XHCI specs (Rev 1.0, 5/21/10) section 6.4.2.1 for >>> Transfer event TRBs, the transfer length is bits 0:23 >>> thereby something like below could be valid: >>> >>> /* Transfer event TRB length bit mask */ >>> /* bits 0:23 */ >>> #define EVENT_TRB_LEN(p) ((p) & 0xffffff) >>> >>> This difference is confusing somewhat. >>> I hope the current code must be pretty much fine, and there could be >>> something that i might be stupidly missing. >> >> Nope, you've caught an honest-to-goodness bug. :) > > Hmm. > >> >> Would you like to submit a patch to fix this? It should be pretty easy >> to look at the context in xhci-ring.c and figure out whether the >> function is queueing a TRB (and thus should use the TRB_LEN macro) or >> handling a event TRB (and should be using the new EVENT_TRB_LEN macro). >> > > Sure, will send a patch for this. > Please refer to patch: usb: xhci: Fix TRB transfer length macro used for Event TRB. -- Thanks & Regards Vivek -- 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
