On Mon, Jun 16, 2014 at 12:30:26PM +0100, [email protected] wrote: > From: Oscar Mateo <[email protected]> > > Otherwise, we might receive a new interrupt before we have time to ack the > first > one, eventually missing it.
Without a atomic xchg operation with mmio space, we merely reduce the window. This is even more apparent when you consider how heavyweight those I915_READ/I915_WRITE are. > According to BSPec, the right order should be: > > 1 - Disable Master Interrupt Control. > 2 - Find the source(s) of the interrupt and clear the Interrupt Identity bits > (IIR) > 4 - Process the interrupt(s) that had bits set in the IIRs. > 5 - Re-enable Master Interrupt Control. > > We maintain the "disable SDE interrupts when handling" hack since apparently > it works. > > Spotted by Bob Beckett <[email protected]>. > > Signed-off-by: Oscar Mateo <[email protected]> I'd like the changelog slightly clarified, and the notes here would be useful in the code as well to describe the theory of operation in handling IRQ. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/intel-gfx
