On 12/05/2012 03:01 AM, Joseph Lo wrote: > The powered-down state of Tegra20 requires power gating both CPU cores. > When the secondary CPU requests to enter powered-down state, it saves > its own contexts and then enters WFI. The Tegra20 had a limition to > power down both CPU cores. The secondary CPU must waits for CPU0 in > powered-down state too. If the secondary CPU be woken up before CPU0 > entering powered-down state, then it needs to restore its CPU states > and waits for next chance. > > Be aware of that, you may see the legacy power state "LP2" in the code > which is exactly the same meaning of "CPU power down".
> diff --git a/arch/arm/mach-tegra/cpuidle-tegra20.c > b/arch/arm/mach-tegra/cpuidle-tegra20.c > +static int __cpuinit tegra20_idle_lp2(struct cpuidle_device *dev, > + return (entered_lp2) ? index : 0; No need for the brackets there. BTW, could you Cc Colin Cross on any future revisions of these patches; it'd be good to get his take on them. > diff --git a/arch/arm/mach-tegra/sleep-tegra20.S > b/arch/arm/mach-tegra/sleep-tegra20.S > +/* > + * tegra_pen_lock > + * on cpu 0: > + * SCRATCH38 = r2 = flag[0] > + * SCRATCH39 = r3 = flag[1] It would be slightly clearer if that was written: * r2 = flag[0] (in SCRATCH38) * r3 = flag[1] (in SCRATCH39) since the meaning of r2/r3 is what's being selected. > + mov r12, #1 > + str r12, [r2] @ flag[cpu] = 1 > + dsb > + str r12, [r1] @ !turn = cpu Should that be "str r0, [r1]"? Otherwise, you're always writing 1 there, not writing the CPU ID as expected. -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
