On Tue, 9 Jun 2009, Sarah Sharp wrote: > On Tue, Apr 28, 2009 at 11:45:23AM +0100, David Vrabel wrote: > > Sarah Sharp wrote: > > > Allow device drivers to submit URBs to bulk endpoints on devices under an > > > xHCI host controller. Share code between the control and bulk enqueueing > > > functions when it makes sense. > > > > > > To get the best performance out of bulk transfers, SuperSpeed devices must > > > have the bMaxBurst size copied from their endpoint companion controller > > > into the xHCI device context. This allows the host controller to "burst" > > > up to 16 packets before it has to wait for the device to acknowledge the > > > first packet. > > > > Your usb_hcd may need to provide a endpoint_reset method to reset the > > sequence number. usb_hcd_reset_endpoint() is called after a > > ClearFeature(Halt) etc. > > Can the endpoint_reset method be called in interrupt context? I need to > issue a command to the xHCI host controller hardware and wait on that > command to complete before a driver can successfully submit new URBs for > that endpoint. This should have been documented better. It was my understanding that the endpoint_reset method is _never_ called in interrupt context. Now I have to go back and recheck one of my EHCI patches... :-) > There are a couple different entry points to the HCD endpoint_reset() > function. Not really. The only entry point is in usb_hcd_reset_endpoint(), which is called only from usb_reset_endpoint(). But _that_ function is called from the various places you note. > One is in message.c, but that has a note that the function > can't be called in interrupt context. It's obvious after a quick read > that two other entry points (drivers/isdn/hisax/st5481_usb.c's > usb_ctrl_complete() and usbfs' proc_resetep()) aren't called in > interrupt context. In fact hisax/st5481_usb's usb_ctrl_complete() usually runs in interrupt context and _always_ runs with interrupts disabled. > That leaves the last entry points in the MSD driver and the UB driver. > I'm not sure whether these functions can be called in interrupt context > or not: > - drivers/usb/storage/transport.c usb_stor_clear_halt() Always in process context. > - drivers/block/ub.c ub_scsi_urb_compl() > > David and Pete, can you help me figure this out? Alan Stern -- 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
