On Fri, 26 Jun 2009 01:07:47 +0800 Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > On Thu, 25 Jun 2009, Alek Du wrote: > > > Alan, > > > > thanks for review for so long a time. I'd like to use this version - it seems cleaner than previous ones. > > By "this version", you mean your 1/4 v3 patch? I disagree -- it's a > mistake to put a ehci_qh_hw pointer in ehci_shadow. > > The reason is simple: The shadow pointers are what the driver uses to > traverse the software structures, just as hw_next pointers are what the > controller uses to traverse the hardware structures. Hence the shadow > pointers should always point to software structures. > > If ehci_itd, ehci_sitd, and ehci_fstn were broken up the same way, I'd > say the same thing about them. > > If you follow my suggestion, you will save one uncached access each > time periodic_next_shadow() encounters a QH. And you should also be > able to eliminate the backpointer from the hw structure, thereby saving > additional precious space in SRAM. > > Alan Stern > Alan, Ok, I'm following your way to create the new patch, will post it later after testing. Thanks, Alek -- 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
