On Tue, Apr 12, 2005 at 09:50:15AM -0400, Alan Stern wrote: > On Tue, 12 Apr 2005, Greg KH wrote: > > > The file pci.ids is slated to go away (see > > Documentation/feature-removal-schedule.txt for more details), not the > > pci_ids.h file. It doesn't bother me to have local pci ids, if you are > > ok with it. > > Okay, then I'll leave it as it stands. > > What about the question of making sure that I/O operations complete before > starting a delay loop, like this: > > outw(..., ...); > mb(); > udelay(10); > > Is the mb() sufficient to insure that the data will be written to the > device before the udelay() call begins?
No. mb is a memory barrier, and as such the compiler will not optimise around it. It has nothing to do with io barriers, which is what you need, correct? Try doing a read after the write, that should do what you need for pci devices. Don't remember what to do for other types, need to go check LDD3 :) thanks, greg k-h ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
