On Wed, 17 Mar 2010, Jason Wessel wrote: > On 03/17/2010 09:30 AM, Alan Stern wrote: > > On Tue, 16 Mar 2010, Jason Wessel wrote: > > > > > >> Part of having the console stable requires that usb sysrq handler get > >> executed in a tasklet. The hcd device lock is always held while the > >> driver call backs are executed. The means you cannot get the sysrq > >> printk's out to the usb console device after the in_flight urb queue > >> is filled. > >> > > > > Either I don't understand this comment properly or else it is simply > > wrong. HCDs do not continue to hold their locks when handing completed > > URBs back to drivers. The giveback call occurs with interrupts > > disabled, but no locks are held. > > > > > > The call back from the urb processing holds a lock. Which callback and which lock, exactly? Surely not the "hcd device lock" as your description says, and maybe not the "driver call back". 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
