Messages in this thread | | | Date | Mon, 18 May 2015 01:19:18 -0400 (EDT) | From | Nicolas Pitre <> | Subject | Re: [linux-sunxi] [RFC 0/7] ARM: sun9i: SMP support with Multi-Cluster Power Management |
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On Sun, 17 May 2015, Maxime Ripard wrote:
> Hi Ian, > > On Sat, May 16, 2015 at 11:08:46AM +0100, Ian Campbell wrote: > > On Thu, 2015-05-14 at 14:10 +0800, Chen-Yu Tsai wrote: > > > This is my attempt to support SMP and CPU hot plugging on the Allwinner > > > A80 SoC. The A80 is a big.Little processor with 2 clusters of 4x Cortex-A7 > > > and 4x Cortex-A15 cores. > > > > I thought there was a preference these days to support this sort of > > thing via support PSCI in the firmware, which allows for other things > > such as non-secure-world etc. > > Yes, it is the preferred way. Meaning that if someone wants to do that > work, he's very much welcome and encouraged to do so. But if no one's > doing it, then we still have to have a way to bringup the secondary > CPUs.
And doing so in the kernel (at least initially) is simpler, and so much easier to fix when it is broken. We've seen a few systems already where power management is crippled because no one is able/allowed/willing to fix the broken firmware.
Nicolas
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