[solved] i.MX6Q has only two cores???

[steffendoster]

Hi again,

I noticed, that my Linux-Installation only recognizes two cpu-cores of the installed i.MX6Q, but I don't know why

Here is the configuration in my Device-Tree (copied from FSL SabreSD)

[CODE]

cpus {
#address-cells = <1>;
#size-cells = <0>;

cpu@0 {
compatible = "arm,cortex-a9";
device_type = "cpu";
reg = <0>;
next-level-cache = <&L2>;
operating-points = <
/* kHz    uV */
1200000 1275000
996000  1250000
852000  1250000
792000  1150000
396000  975000
>;
fsl,soc-operating-points = <
/* ARM kHz  SOC-PU uV */
1200000 1275000
996000 1250000
852000 1250000
792000 1175000
396000 1175000
>;
clock-latency = ; /* two CLK32 periods */
clocks = <&clks IMX6QDL_CLK_ARM>,
<&clks IMX6QDL_CLK_PLL2_PFD2_396M>,
<&clks IMX6QDL_CLK_STEP>,
<&clks IMX6QDL_CLK_PLL1_SW>,
<&clks IMX6QDL_CLK_PLL1_SYS>;
clock-names = "arm", "pll2_pfd2_396m", "step",
       "pll1_sw", "pll1_sys";
arm-supply = <&reg_arm>;
pu-supply = <&reg_pu>;
soc-supply = <&reg_soc>;
};

cpu@1 {
compatible = "arm,cortex-a9";
device_type = "cpu";
reg = ;
next-level-cache = <&L2>;
};

cpu@2 {
compatible = "arm,cortex-a9";
device_type = "cpu";
reg = ;
next-level-cache = <&L2>;
};

cpu@3 {
compatible = "arm,cortex-a9";
device_type = "cpu";
reg = ;
next-level-cache = <&L2>;
};
};  [/CODE]

Why does Linux see only two cores?

[steffendoster · Accepted solution]

Well, I'm very sorry to say that, but it was a hardware-failure. The Voltage supply was configured for a i.MX6D. By this way, two of the Cores weren't able to start.

I fixed it, and now we have the foll Quad-Core Performance.

Again, sorry for that.

[gusarambula]

Hello steffen,

I'm glad you found the root cause! Thank you for updating this thread so it may help other community users!

[sinanakman]

Hi Steffen

Is it possible that you might have set the number

of CPUs to only 2 in while configuring the kernel.

You might want to verify that CONFIG_NR_CPUS is 4.

Hope this helps

Sinan Akman

[steffendoster]

No, sorry, is set to 4.

I took the imx_v6_v7_defconfig as template.

[gusarambula]

Hello Steffen,

It is weird that you’re not seeing all four cores if these are set on the kernel configuration and the device tree. Which machine configuration did you use in Yocto and what kernel version are you using?  Perhaps you can attach the defconfig file as well.

[steffendoster]

I don't use Yocto. I'm currently using Debian 8 with a self-compiled 3.19 Kernel.

My Kernelconfig is attached.