cpufreq: Make sure CPU is running on a freq from freq-table
authorViresh Kumar <viresh.kumar@linaro.org>
Tue, 3 Dec 2013 05:50:46 +0000 (11:20 +0530)
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>
Mon, 6 Jan 2014 13:17:25 +0000 (14:17 +0100)
commitd3916691c90dfc9f08328d5cef8181e9ea508c55
treee32b3422823ef3a64a42c1c72785a169fff20a9c
parentae6b427132ba39d023e332e7d920e9931ff05313
cpufreq: Make sure CPU is running on a freq from freq-table

Sometimes boot loaders set CPU frequency to a value outside of frequency table
present with cpufreq core. In such cases CPU might be unstable if it has to run
on that frequency for long duration of time and so its better to set it to a
frequency which is specified in freq-table. This also makes cpufreq stats
inconsistent as cpufreq-stats would fail to register because current frequency
of CPU isn't found in freq-table.

Because we don't want this change to affect boot process badly, we go for the
next freq which is >= policy->cur ('cur' must be set by now, otherwise we will
end up setting freq to lowest of the table as 'cur' is initialized to zero).

In case current frequency doesn't match any frequency from freq-table, we throw
warnings to user, so that user can get this fixed in their bootloaders or
freq-tables.

Reported-by: Carlos Hernandez <ceh@ti.com>
Reported-and-tested-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
drivers/cpufreq/cpufreq.c
drivers/cpufreq/freq_table.c
include/linux/cpufreq.h