linux/drivers/cpufreq
Mikulas Patocka d82b922a4a powernow-k6: correctly initialize default parameters
The powernow-k6 driver used to read the initial multiplier from the
powernow register. However, there is a problem with this:

* If there was a frequency transition before, the multiplier read from the
  register corresponds to the current multiplier.
* If there was no frequency transition since reset, the field in the
  register always reads as zero, regardless of the current multiplier that
  is set using switches on the mainboard and that the CPU is running at.

The zero value corresponds to multiplier 4.5, so as a consequence, the
powernow-k6 driver always assumes multiplier 4.5.

For example, if we have 550MHz CPU with bus frequency 100MHz and
multiplier 5.5, the powernow-k6 driver thinks that the multiplier is 4.5
and bus frequency is 122MHz. The powernow-k6 driver then sets the
multiplier to 4.5, underclocking the CPU to 450MHz, but reports the
current frequency as 550MHz.

There is no reliable way how to read the initial multiplier. I modified
the driver so that it contains a table of known frequencies (based on
parameters of existing CPUs and some common overclocking schemes) and sets
the multiplier according to the frequency. If the frequency is unknown
(because of unusual overclocking or underclocking), the user must supply
the bus speed and maximum multiplier as module parameters.

This patch should be backported to all stable kernels. If it doesn't
apply cleanly, change it, or ask me to change it.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-01-06 15:52:49 +01:00
..
acpi-cpufreq.c Merge branch 'pm-cpufreq' 2013-11-07 19:26:02 +01:00
amd_freq_sensitivity.c cpufreq: AMD "frequency sensitivity feedback" powersave bias for ondemand governor 2013-04-10 13:19:26 +02:00
arm_big_little_dt.c PM / OPP: rename header to linux/pm_opp.h 2013-10-25 22:33:23 +02:00
arm_big_little.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
arm_big_little.h cpufreq: arm_big_little: add in-kernel switching (IKS) support 2013-10-31 00:10:53 +01:00
at32ap-cpufreq.c cpufreq_ at32ap-cpufreq.c: Fix section mismatch 2013-12-10 08:46:38 +01:00
blackfin-cpufreq.c cpufreq: move freq change notifications to cpufreq core 2013-10-31 00:11:08 +01:00
cpufreq_conservative.c cpufreq: conservative: set requested_freq to policy max when it is over policy max 2013-11-12 23:18:20 +01:00
cpufreq_governor.c cpufreq: Fix timer/workqueue corruption by protecting reading governor_enabled 2014-01-06 01:22:02 +01:00
cpufreq_governor.h cpufreq: Fix timer/workqueue corruption by protecting reading governor_enabled 2014-01-06 01:22:02 +01:00
cpufreq_ondemand.c cpufreq: ondemand: Remove redundant return statement 2013-11-01 00:44:34 +01:00
cpufreq_performance.c cpufreq: Clean up header files included in the core 2013-08-07 23:34:09 +02:00
cpufreq_powersave.c cpufreq: Clean up header files included in the core 2013-08-07 23:34:09 +02:00
cpufreq_stats.c cpufreq: Fix wrong time unit conversion 2013-09-10 02:49:46 +02:00
cpufreq_userspace.c cpufreq / governor: Remove fossil comment 2013-10-17 23:00:20 +02:00
cpufreq-cpu0.c cpufreq: cpufreq-cpu0: clk_round_rate() can return a zero upon error 2013-12-06 23:19:19 +01:00
cpufreq-nforce2.c cpufreq: nforce2: don't initialize part of policy set by core 2013-10-16 00:50:29 +02:00
cpufreq.c cpufreq: Make sure CPU is running on a freq from freq-table 2014-01-06 14:17:25 +01:00
cris-artpec3-cpufreq.c cpufreq: move freq change notifications to cpufreq core 2013-10-31 00:11:08 +01:00
cris-etraxfs-cpufreq.c cpufreq: move freq change notifications to cpufreq core 2013-10-31 00:11:08 +01:00
davinci-cpufreq.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
dbx500-cpufreq.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
e_powersaver.c cpufreq: move freq change notifications to cpufreq core 2013-10-31 00:11:08 +01:00
elanfreq.c cpufreq: move freq change notifications to cpufreq core 2013-10-31 00:11:08 +01:00
exynos4x12-cpufreq.c cpufreq: exynos: Remove unwanted EXPORT_SYMBOL 2013-11-20 23:55:38 +01:00
exynos4210-cpufreq.c cpufreq: exynos: Remove unwanted EXPORT_SYMBOL 2013-11-20 23:55:38 +01:00
exynos5250-cpufreq.c cpufreq: exynos5250: Set APLL rate using CCF API 2014-01-06 01:26:00 +01:00
exynos5440-cpufreq.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
exynos-cpufreq.c cpufreq: exynos: Convert exynos-cpufreq to platform driver 2014-01-06 14:29:24 +01:00
exynos-cpufreq.h cpufreq: fix EXYNOS drivers selection 2013-08-12 12:00:21 +05:30
freq_table.c cpufreq: Make sure CPU is running on a freq from freq-table 2014-01-06 14:17:25 +01:00
gx-suspmod.c cpufreq: gx: don't initialize part of policy set by core 2013-10-16 00:50:30 +02:00
highbank-cpufreq.c cpufreq: highbank-cpufreq: Enable Midway/ECX-2000 2013-10-17 00:53:08 +02:00
ia64-acpi-cpufreq.c cpufreq: move freq change notifications to cpufreq core 2013-10-31 00:11:08 +01:00
imx6q-cpufreq.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
integrator-cpufreq.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
intel_pstate.c Merge back earlier 'pm-cpufreq' material. 2014-01-05 15:32:51 +01:00
Kconfig cpufreq: Select PM_OPP rather than depending on it 2013-12-22 22:03:49 +01:00
Kconfig.arm cpufreq: imx6q-cpufreq driver is reused on i.MX6 series SoCs 2014-01-06 13:33:45 +01:00
Kconfig.powerpc cpufreq: remove CONFIG_CPU_FREQ_TABLE 2013-10-16 00:50:33 +02:00
Kconfig.x86 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-11-15 16:47:22 -08:00
kirkwood-cpufreq.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
longhaul.c cpufreq: Implement light weight ->target_index() routine 2013-10-25 22:42:24 +02:00
longhaul.h cpufreq: delete __cpuinit usage from all cpufreq files 2013-07-14 19:36:57 -04:00
longrun.c cpufreq: add new routine cpufreq_verify_within_cpu_limits() 2013-10-16 00:50:23 +02:00
loongson2_cpufreq.c cpufreq: move freq change notifications to cpufreq core 2013-10-31 00:11:08 +01:00
Makefile cpufreq: arm_big_little: add vexpress SPC interface driver 2013-10-30 00:48:26 +01:00
maple-cpufreq.c cpufreq: move freq change notifications to cpufreq core 2013-10-31 00:11:08 +01:00
omap-cpufreq.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
p4-clockmod.c cpufreq: move freq change notifications to cpufreq core 2013-10-31 00:11:08 +01:00
pasemi-cpufreq.c ACPI and power management updates for 3.13-rc1 2013-11-14 13:41:48 +09:00
pcc-cpufreq.c cpufreq: send new set of notification for transition failures 2014-01-06 01:43:44 +01:00
pmac32-cpufreq.c cpufreq: move freq change notifications to cpufreq core 2013-10-31 00:11:08 +01:00
pmac64-cpufreq.c cpufreq: move freq change notifications to cpufreq core 2013-10-31 00:11:08 +01:00
powernow-k6.c powernow-k6: correctly initialize default parameters 2014-01-06 15:52:49 +01:00
powernow-k7.c cpufreq: Implement light weight ->target_index() routine 2013-10-25 22:42:24 +02:00
powernow-k7.h [CPUFREQ] Move x86 drivers to drivers/cpufreq/ 2011-05-19 18:51:07 -04:00
powernow-k8.c cpufreq: send new set of notification for transition failures 2014-01-06 01:43:44 +01:00
powernow-k8.h cpufreq: Remove support for hardware P-state chips from powernow-k8 2012-09-09 22:05:30 +02:00
ppc_cbe_cpufreq_pervasive.c cpufreq: powerpc/platforms/cell: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:26 +02:00
ppc_cbe_cpufreq_pmi.c cpufreq: powerpc/platforms/cell: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:26 +02:00
ppc_cbe_cpufreq.c cpufreq: move freq change notifications to cpufreq core 2013-10-31 00:11:08 +01:00
ppc_cbe_cpufreq.h cpufreq: powerpc/platforms/cell: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:26 +02:00
ppc-corenet-cpufreq.c cpufreq: move freq change notifications to cpufreq core 2013-10-31 00:11:08 +01:00
pxa2xx-cpufreq.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
pxa3xx-cpufreq.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
s3c24xx-cpufreq-debugfs.c cpufreq: s3c24xx: move cpufreq driver to drivers/cpufreq 2013-05-20 23:04:28 +09:00
s3c24xx-cpufreq.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
s3c64xx-cpufreq.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
s3c2410-cpufreq.c cpufreq: s3c24xx: move cpufreq driver to drivers/cpufreq 2013-05-20 23:04:28 +09:00
s3c2412-cpufreq.c cpufreq: s3c24xx: move cpufreq driver to drivers/cpufreq 2013-05-20 23:04:28 +09:00
s3c2416-cpufreq.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
s3c2440-cpufreq.c cpufreq: s3c2440: Staticize local variables 2014-01-06 01:18:33 +01:00
s5pv210-cpufreq.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
sa1100-cpufreq.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
sa1110-cpufreq.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
sc520_freq.c cpufreq: move freq change notifications to cpufreq core 2013-10-31 00:11:08 +01:00
sh-cpufreq.c cpufreq: sh: don't initialize part of policy set by core 2013-10-16 00:50:32 +02:00
sparc-us2e-cpufreq.c cpufreq: move freq change notifications to cpufreq core 2013-10-31 00:11:08 +01:00
sparc-us3-cpufreq.c cpufreq: move freq change notifications to cpufreq core 2013-10-31 00:11:08 +01:00
spear-cpufreq.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
speedstep-centrino.c cpufreq: move freq change notifications to cpufreq core 2013-10-31 00:11:08 +01:00
speedstep-ich.c cpufreq: move freq change notifications to cpufreq core 2013-10-31 00:11:08 +01:00
speedstep-lib.c cpufreq: Add support for x86 cpuinfo auto loading v4 2012-01-26 16:49:06 -08:00
speedstep-lib.h [CPUFREQ] Move x86 drivers to drivers/cpufreq/ 2011-05-19 18:51:07 -04:00
speedstep-smi.c cpufreq: move freq change notifications to cpufreq core 2013-10-31 00:11:08 +01:00
tegra-cpufreq.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
unicore2-cpufreq.c cpufreq: send new set of notification for transition failures 2014-01-06 01:43:44 +01:00
vexpress-spc-cpufreq.c cpufreq: arm_big_little: add vexpress SPC interface driver 2013-10-30 00:48:26 +01:00