On Mon, Oct 19, 2009 at 03:29, Hennerich, Michael wrote: >From: Mike Frysinger >>On Fri, Oct 16, 2009 at 05:02, Zhang, Sonic wrote: >>> Write to XMT_DATA8 register should be done after INT_STAT is cleared. >>> So, as least one sync before XMIT_DATA8 is necessary. >>> I will do a bit clean up. >>> >>> Yes, a SSYNC_ATOMIC() macro is better for interrupt routine usage. >> >>Michael pointed out something not so obvious (at least to me) ... >>higher priority interrupts can still interrupt things, so >>SSYNC_ATOMIC() would only be usable if the irq handler were registered >>w/IRQF_DISABLED. and people really hate when you use that flag. > > Besides that - you should also keep in mind that Linux uses DELAYED > DISABLE. > This means if you disable an IRQ - it's not disabled until it actually > triggered. > They use this concept, because interrupt enable/disable can take quite > long on some architecture.
thanks, i wasnt aware of that. guess the only place this has a use is exception/early context. and we already use the builtin there. -mike _______________________________________________ Linux-kernel-commits mailing list [email protected] https://blackfin.uclinux.org/mailman/listinfo/linux-kernel-commits
