Re: [PATCH v4 4/5] arm64/perf: Enable PMCR long cycle counter bit

From: Will Deacon
Date: Thu Feb 18 2016 - 12:34:26 EST


On Thu, Feb 18, 2016 at 05:50:13PM +0100, Jan Glauber wrote:
> With the long cycle counter bit (LC) disabled the cycle counter is not
> working on ThunderX SOC (ThunderX only implements Aarch64).
> Also, according to documentation LC == 0 is deprecated.
>
> To keep the code simple the patch does not introduce 64 bit wide counter
> functions. Instead writing the cycle counter always sets the upper
> 32 bits so overflow interrupts are generated as before.
>
> Original patch from Andrew Pinksi <Andrew.Pinksi@xxxxxxxxxxxxxxxxxx>

What does this mean? Do we need Andrew's S-o-B, or is this a fresh patch?

Will