On Fri, 2012-12-21 at 01:43 +0800, Stephen Warren wrote: > On 12/17/2012 07:30 PM, 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 > > > int __init tegra20_cpuidle_init(void) > > > + drv->state_count = sizeof(tegra_idle_states) / > > + sizeof(struct cpuidle_state); > > Use ARRAY_SIZE() there? > OK. > > > + for (i = 0; i < drv->state_count; i++) > > + memcpy(&drv->states[i], &tegra_idle_states[i], > > + sizeof(struct cpuidle_state)); > > Can't you call memcpy() once: > > memcpy(drv->states, tegra_idle_states, > drv->state_count * sizeof(drv->states[0])); > > ... although I personally much preferred when all this was just static > initialization directly in tegra_idle_driver, rather than all this messy > copying. Really, struct cpuidle_driver should point at the array, rather > than including it. > I think so. If you strongly prefer the original style, I can rollback to the previous version here. > > diff --git a/arch/arm/mach-tegra/pm.c b/arch/arm/mach-tegra/pm.c > > > @@ -173,6 +173,8 @@ bool __cpuinit tegra_set_cpu_in_lp2(int phy_cpu_id) > > > > if ((phy_cpu_id == 0) && cpumask_equal(cpu_lp2_mask, cpu_online_mask)) > > last_cpu = true; > > + else if (phy_cpu_id == 1) > > + tegra20_cpu_set_resettable_soon(); > > > > spin_unlock(&tegra_lp2_lock); > > return last_cpu; > > Shouldn't the code in that else branch have a run-time check for whether > it's running on Tegra20? When compiled without Tegra20 support, > tegra20_cpu_set_resettable_soon() is a dummy static inline, but when > both Tegra20 and Tegra30 are compiled in, isn't that code going to run > when it shouldn't; pm.c being a common file. > Because the code didn't hurt Tegra30, so I didn't add a runtime detection there. If you have concern, I can add runtime detection there. Thanks, Joseph -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
