9801522840
CPUFREQ_CONST_LOOPS was introduced in a very old commit from pre-2.6
kernel release by commit 6a4a93f9c0d5 ("[CPUFREQ] Fix 'out of sync'
issue").
Basically, that commit does two things:
- It adds the frequency verification code (which is quite similar to
what we have today as well).
- And it sets the CPUFREQ_CONST_LOOPS flag only for setpolicy drivers,
rightly so based on the code we had then. The idea was to avoid
frequency validation for setpolicy drivers as the cpufreq core doesn't
know what frequency the hardware is running at and so no point in
doing frequency verification.
The problem happened when we started to use the same CPUFREQ_CONST_LOOPS
flag for constant loops-per-jiffy thing as well and many has_target()
drivers started using the same flag and unknowingly skipped the
verification of frequency. There is no logical reason behind skipping
frequency validation because of the presence of CPUFREQ_CONST_LOOPS
flag otherwise.
Fix this issue by skipping frequency validation only for setpolicy
drivers and always doing it for has_target() drivers irrespective of
the presence or absence of CPUFREQ_CONST_LOOPS flag.
cpufreq_notify_transition() is only called for has_target() type driver
and not for set_policy type, and the check is simply redundant. Remove
it as well.
Also remove () around freq comparison statement as they aren't required
and checkpatch also warns for them.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.