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Date: Fri, 23 Jan 2015 15:59:06 +1100 (AEDT) From: Michael Ellerman <mpe@...erman.id.au> To: Preeti U Murthy <preeti@...ux.vnet.ibm.com>, rafael.j.wysocki@...el.com Cc: linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org Subject: Re: cpuidle/powernv: Read target_residency value of idle states from DT if available On Tue, 2015-20-01 at 11:26:49 UTC, Preeti U Murthy wrote: > @@ -177,34 +178,39 @@ static int powernv_add_idle_states(void) > return nr_idle_states; > } > > - idle_state_latency = of_get_property(power_mgt, > - "ibm,cpu-idle-state-latencies-ns", NULL); > - if (!idle_state_latency) { > + dt_idle_states = len_flags / sizeof(u32); > + > + latency_ns = kzalloc(sizeof(*latency_ns) * dt_idle_states, GFP_KERNEL); > + rc = of_property_read_u32(power_mgt, > + "ibm,cpu-idle-state-latencies-ns", latency_ns); That's only reading the first value. If you want to read the full property you need the _array version. > + if (rc) { > pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-latencies-ns\n"); You missed my hint that "DT-PowerMgmt" is a weird and ugly prefix. Can you use "cpuidle-powernv:" instead? > > - dt_idle_states = len_flags / sizeof(u32); > + residency_ns = kzalloc(sizeof(*residency_ns) * dt_idle_states, GFP_KERNEL); > + rc = of_property_read_u32(power_mgt, > + "ibm,cpu-idle-state-residency-ns", residency_ns); > + if (rc) { > + pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-residency-ns\n"); > + pr_warn("Falling back to default values\n"); I don't think this is worth a warning seeing as we know there are firmwares out there which do not have the property. > for (i = 0; i < dt_idle_states; i++) { > > flags = be32_to_cpu(idle_state_flags[i]); > - > - /* Cpuidle accepts exit_latency in us and we estimate > - * target residency to be 10x exit_latency > + /* > + * Cpuidle accepts exit_latency and target_residency in us. > + * Use default target_residency values if f/w does not expose it. > */ > - latency_ns = be32_to_cpu(idle_state_latency[i]); > if (flags & OPAL_PM_NAP_ENABLED) { > /* Add NAP state */ > strcpy(powernv_states[nr_idle_states].name, "Nap"); > strcpy(powernv_states[nr_idle_states].desc, "Nap"); > powernv_states[nr_idle_states].flags = 0; > - powernv_states[nr_idle_states].exit_latency = > - ((unsigned int)latency_ns) / 1000; > - powernv_states[nr_idle_states].target_residency = > - ((unsigned int)latency_ns / 100); > + powernv_states[nr_idle_states].target_residency = 100; > powernv_states[nr_idle_states].enter = &nap_loop; > - nr_idle_states++; That looks wrong? Or do you mean to do that? cheers -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.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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