Hi,
We want to migrate one of our TK1-based products from the downstream kernel 3.10 to the mainline kernel (which means we are using the machine apalis-tk1-mainline). The applications needs a lot of computing power and it’s crucial to disable all limitating factors, e.g. scaling governours, cpuquiet, usb suspend, etc. One important point was to set the EMC frequency to maximum, which was done via the sysfs entry “/sys/kernel/debug/clock/override.emc/”. However, i cannot find this entry any more. How can we maximize the EMC frequency in the mainline kernel?
Regards
Which exact part of the regular Linux mainline cpufreq support is it that is not working for you?
root@apalis-tk1-mainline:~# cpufreq-info
cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to cpufreq@vger.kernel.org, please.
analyzing CPU 0:
driver: cpufreq-dt
CPUs which run at the same hardware frequency: 0 1 2 3
CPUs which need to have their frequency coordinated by software: 0 1 2 3
maximum transition latency: 300 us.
hardware limits: 204 MHz - 2.12 GHz
available frequency steps: 204 MHz, 306 MHz, 408 MHz, 510 MHz, 612 MHz, 714 MHz, 816 MHz, 918 MHz, 1.02 GHz, 1.12 GHz, 1.22 GHz, 1.33 GHz, 1.43 GHz, 1.53 GHz, 1.63 GHz, 1.73 GHz, 1.84 GHz, 1.94 GHz, 2.01 GHz, 2.12 GHz
available cpufreq governors: ondemand, performance
current policy: frequency should be within 204 MHz and 2.12 GHz.
The governor "ondemand" may decide which speed to use
within this range.
current CPU frequency is 1.84 GHz (asserted by call to hardware).
analyzing CPU 1:
driver: cpufreq-dt
CPUs which run at the same hardware frequency: 0 1 2 3
CPUs which need to have their frequency coordinated by software: 0 1 2 3
maximum transition latency: 300 us.
hardware limits: 204 MHz - 2.12 GHz
available frequency steps: 204 MHz, 306 MHz, 408 MHz, 510 MHz, 612 MHz, 714 MHz, 816 MHz, 918 MHz, 1.02 GHz, 1.12 GHz, 1.22 GHz, 1.33 GHz, 1.43 GHz, 1.53 GHz, 1.63 GHz, 1.73 GHz, 1.84 GHz, 1.94 GHz, 2.01 GHz, 2.12 GHz
available cpufreq governors: ondemand, performance
current policy: frequency should be within 204 MHz and 2.12 GHz.
The governor "ondemand" may decide which speed to use
within this range.
current CPU frequency is 1.84 GHz (asserted by call to hardware).
analyzing CPU 2:
driver: cpufreq-dt
CPUs which run at the same hardware frequency: 0 1 2 3
CPUs which need to have their frequency coordinated by software: 0 1 2 3
maximum transition latency: 300 us.
hardware limits: 204 MHz - 2.12 GHz
available frequency steps: 204 MHz, 306 MHz, 408 MHz, 510 MHz, 612 MHz, 714 MHz, 816 MHz, 918 MHz, 1.02 GHz, 1.12 GHz, 1.22 GHz, 1.33 GHz, 1.43 GHz, 1.53 GHz, 1.63 GHz, 1.73 GHz, 1.84 GHz, 1.94 GHz, 2.01 GHz, 2.12 GHz
available cpufreq governors: ondemand, performance
current policy: frequency should be within 204 MHz and 2.12 GHz.
The governor "ondemand" may decide which speed to use
within this range.
current CPU frequency is 1.84 GHz (asserted by call to hardware).
analyzing CPU 3:
driver: cpufreq-dt
CPUs which run at the same hardware frequency: 0 1 2 3
CPUs which need to have their frequency coordinated by software: 0 1 2 3
maximum transition latency: 300 us.
hardware limits: 204 MHz - 2.12 GHz
available frequency steps: 204 MHz, 306 MHz, 408 MHz, 510 MHz, 612 MHz, 714 MHz, 816 MHz, 918 MHz, 1.02 GHz, 1.12 GHz, 1.22 GHz, 1.33 GHz, 1.43 GHz, 1.53 GHz, 1.63 GHz, 1.73 GHz, 1.84 GHz, 1.94 GHz, 2.01 GHz, 2.12 GHz
available cpufreq governors: ondemand, performance
current policy: frequency should be within 204 MHz and 2.12 GHz.
The governor "ondemand" may decide which speed to use
within this range.
current CPU frequency is 1.84 GHz (asserted by call to hardware).
root@apalis-tk1-mainline:~# cat /sys/kernel/debug/emc/supported_rates
12750000 20400000 40800000 68000000 102000000 204000000 300000000 396000000 528000000 600000000 792000000 924000000
root@apalis-tk1-mainline:~# cat /sys/kernel/debug/emc/rate
924000000
I can confirm that the cpufreq support for the EMC is working. Thanks.
You are very welcome.