Messages in this thread |  | | | Date | Mon, 14 Sep 2009 15:58:24 +0300 | | Subject | Re: [PATCH] arm: remove unused code in delay.S | | From | Felipe Contreras <> |
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On Mon, Sep 14, 2009 at 11:10 AM, Russell King - ARM Linux <linux@arm.linux.org.uk> wrote: > On Mon, Sep 14, 2009 at 01:21:00AM +0100, Jamie Lokier wrote: >> Russell King - ARM Linux wrote: >> > On Sun, Sep 13, 2009 at 11:28:47PM +0200, Marek Vasut wrote: >> > > > bhi __delay >> > > > mov pc, lr >> > > > ENDPROC(__udelay) >> > > > >> > > Hi >> > > >> > > why was this code there in the first place ? >> > >> > To make the delay loop more stable and predictable on older CPUs. >> >> So why has it been commented out, if it's needed for that? > > We moved on and it penalises later CPUs, leading to udelay providing > shorter delays than requested. > > So the choice was either stable and predictable on older CPUs but > buggy on newer CPUs, or correct on all CPUs but gives unnecessarily > longer delays on older CPUs.
Why not add an #ifdef CPU_V4 or whatever?
-- Felipe Contreras -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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