Dear Gregory CLEMENT,
On Wed, 25 Feb 2015 19:30:50 +0100, Gregory CLEMENT wrote:
> On Armada 38x SoCs, under heavy I/O load, the system hangs when CPU
> Idle is enabled. Waiting for a solution to this issue, this patch
> disables the CPU Idle support for this SoC.
>
> As CPU Hot plug support also uses some of the CPU Idle functions it is
> also affected by the same issue. This patch disables it also for the
> Armada 38x SoCs.
>
> Signed-off-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx> # v3.17 +
Tested-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
I tested on Armada 38x, and indeed CPU hotplug is properly disabled,
and it doesn't prevent suspend/resume (not supported yet in mainline,
but hopefully soon to be supported).
Some minor comments below.
> diff --git a/arch/arm/mach-mvebu/pmsu.c b/arch/arm/mach-mvebu/pmsu.c
> index 8b9f5e202ccf..2145f192662f 100644
> --- a/arch/arm/mach-mvebu/pmsu.c
> +++ b/arch/arm/mach-mvebu/pmsu.c
> @@ -415,6 +415,9 @@ static __init int armada_38x_cpuidle_init(void)
> void __iomem *mpsoc_base;
> u32 reg;
>
> + pr_warn("CPU Idle is currently broken on Armada 38x: disabling");
Idle -> idle
> + return 0;
> +
> np = of_find_compatible_node(NULL, NULL,
> "marvell,armada-380-coherency-fabric");
> if (!np)
> @@ -469,13 +472,23 @@ static __init int armada_xp_cpuidle_init(void)
> static int __init mvebu_v7_cpu_pm_init(void)
> {
> struct device_node *np;
> - int ret;
> + int ret = 0;
Not clear why this change is needed.
>
> np = of_find_matching_node(NULL, of_pmsu_table);
> if (!np)
> return 0;
> of_node_put(np);
>
> + /*
> + * Currently the CPU Idle support for Armada 38x is broken, as
> + * the CPU Hotplug uses some of the CPU Idle functions it is
> + * broken too, so let's disable it
> + */
> + if (of_machine_is_compatible("marvell,armada380")) {
> + cpu_hotplug_disable();
> + pr_warn("CPU Hotplug support is currently broken on Armada 38x: disabling");
Hotplug -> hotplug.
Thanks,
Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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