Re: [PATCH v3 1/7] cpufreq: cpufreq-cpu0: allow use of optional boost mode frequencies

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 13.02.2014 09:02, Thomas Abraham wrote:
On Wed, Feb 12, 2014 at 8:28 PM, Tomasz Figa <t.figa@xxxxxxxxxxx> wrote:
Hi Thomas,


On 07.02.2014 16:55, Thomas Abraham wrote:

[snip]

diff --git a/drivers/cpufreq/cpufreq-cpu0.c
b/drivers/cpufreq/cpufreq-cpu0.c
index 0c12ffc..06539eb 100644
--- a/drivers/cpufreq/cpufreq-cpu0.c
+++ b/drivers/cpufreq/cpufreq-cpu0.c
@@ -195,6 +195,9 @@ static int cpu0_cpufreq_probe(struct platform_device
*pdev)
                         transition_latency += ret * 1000;
         }

+       if (of_find_property(cpu_dev->of_node, "boost-frequency", NULL))
+               cpu0_cpufreq_driver.boost_supported = true;
+
         ret = cpufreq_register_driver(&cpu0_cpufreq_driver);
         if (ret) {
                 pr_err("failed register driver: %d\n", ret);


I'd say that boost should be enabled depending on user's preference, as done
before in Exynos cpufreq driver. So both presence of boost-frequency
property and state of CPU_FREQ_BOOST_SW should be considered.

As for CPU_FREQ_BOOST_SW, I don't think it should be always selected, but
ather, either converted to a user-selectable bool entry or made selectable
by other entry, like current ARM_EXYNOS_CPU_FREQ_BOOST_SW.

We still will have the same problem on Exynos multi-platform kernel
where one Exynos platform needs it and others don't. Same with just
using the CPU_FREQ_BOOST_SW config option. So that was the reason to
just fallback on presence of boost property.

I don't think we really have a problem here, because we have well defined semantics for particular enable methods:

- Kconfig is supposed to be a global enable - if an option is disabled, it is not even built into the kernel and can be used in any way - this is per-user choice, regardless of platform the image is going to be running on,

- device tree is supposed to be telling us whether the hardware we are running on supports given feature and all the required data to enable it, if yes,

- then, for per system configuration, you should be able to enable/disable given feature by a command line parameter, e.g. cpufreq.boost_disable.

If you follow the above description, you should be able to get any configuration you want on any system, as long as it's supported by hardware.

Best regards,
Tomasz
--
To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux SoC Development]     [Linux Rockchip Development]     [Linux USB Development]     [Video for Linux]     [Linux Audio Users]     [Linux SCSI]     [Yosemite News]

  Powered by Linux