Touchscreen failure with CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND

[Rafael J. Wysocki]

On Friday, April 21, 2017 01:11:52 PM Fabio Estevam wrote:
> Hi,
> 
> Running 4.11-rc7 on a imx6q-sabresd board I notice that egalax
> touchscreen stops generating evtest events after a random period of
> time.
> 
> This problem can be avoided if I unselect CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND:
> 
> --- a/arch/arm/configs/imx_v6_v7_defconfig
> +++ b/arch/arm/configs/imx_v6_v7_defconfig
> @@ -54,7 +54,6 @@ CONFIG_CMA=y
>  CONFIG_CMDLINE="noinitrd console=ttymxc0,115200"
>  CONFIG_KEXEC=y
>  CONFIG_CPU_FREQ=y
> -CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND=y
>  CONFIG_ARM_IMX6Q_CPUFREQ=y
>  CONFIG_CPU_IDLE=y
>  CONFIG_VFP=y
> 
> With this change evtest always capture all touchscreen events. No
> single failure is seen.
> 
> I could see the same behavior with all mainline kernels I tested (4.9 and 4.10).
> 
> Any ideas as to how fix this bug when CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND=y?

And which governor is the default otherwise?

Thanks,
Rafael