Re: usb_submit_urb from callback

Oliver Neukum <[email protected]>
Newsgroups gmane.linux.usb.devel
Message-ID <[email protected]>
Am Montag 12 November 2007 schrieb Greg KH:
> > > > the second argument must be GFP_ATOMIC. How is URB re-submission
> > > > from within a URB's callback function handled under the 2.4 kernel,
> > without
> > > > the mem_flags argument?
> > >
> > > Might I ask why you are caring about the 2.4 usb stack?  That kernel is
> > > not supported anymore...
> > 
> > We still use 2.4 on our production systems.
> 
> My sympathies :)
> 
> But are you writing a new USB driver for these machine?  If so, for what
> hardware?
> 
> As to your original question, we just guess as to the flags that are
> needed, always using GFP_KERNEL and so, things can break at times.  That
> is why we changed things in the 2.5 development cycle

Specifically, we choose between GFP_ATOMIC and GFP_KERNEL according
to the local interrupt enablement. Never, evr, in 2.4 submit an URB under a
simple spinlock outside an interrupt handler.

	Regards
		Oliver


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