On Thu, 17 May 2007, Pete Zaitcev wrote: > On Thu, 17 May 2007 14:26:18 -0400 (EDT), Alan Stern <[EMAIL PROTECTED]> > wrote: > > > As it happens, USB callbacks cannot be interrupted. That's a somewhat > > artificial restriction; in theory there's no reason we couldn't allow > > interrupts. > > Do you remember why we're doing this? I did not touch that part since > the attempt to keep usb->lock across the callback (read: years back).
I think it's pretty much just legacy. Nobody wants to audit all the callback routines to see which ones really need interrupts to be disabled. > I think we should remove those local_irq_save's, and leave just the > guarantee that it won't be re-entered (currently such a guarantee > is inherited from the Linux's interrupt handling, and we'll only > need to make it explicit if any HCDs start using softirq when > calling the giveback routine). I'm poking your memory in case > there's actually a good reason for it which I forgot. None that I can recall. Even without the interrupt handling guarantee, the HCDs are (or should be) written so that callbacks won't occur recursively. Alan Stern ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
