Re: [PATCH] powerpc: Cell timebase bug workaround
From: Stephen Rothwell <hidden>
Date: 2006-10-09 08:36:52
On Mon, 09 Oct 2006 17:05:17 +1000 Benjamin Herrenschmidt [off-list ref] wrote:
quoted
Why not branch back to the mftb if the lower word is zero (this would also take care of the very unlikely "hitting the bug more than once" case and the "normal" case would then not have to branch at all. (And it uses one less instruction.)Because that would cause us to spinloop for the whole duration of a tb tick in that case, which is pretty bad when the timebase is slow (the slower I've seen so far is 14Mhz).
Right! /me hits himself in the forehead :-) -- Cheers, Stephen Rothwell sfr@canb.auug.org.au http://www.canb.auug.org.au/~sfr/
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