linux/drivers
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
..
accessibility
acpi Merge branch 'acpica' 2013-11-27 01:03:27 +01:00
amba
ata SCSI fixes on 20131206 2013-12-06 08:30:18 -08:00
atm atm: idt77252: fix dev refcnt leak 2013-11-19 15:53:02 -05:00
auxdisplay
base Revert "cpufreq: suspend governors on system suspend/hibernate" 2013-12-08 01:04:17 +01:00
bcma Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2013-11-13 17:40:34 +09:00
block null_blk: mem garbage on NUMA systems during init 2013-12-15 12:17:16 -08:00
bluetooth
bus Merge branch 'for-linus' of git://git.linaro.org/people/rmk/linux-arm 2013-11-14 08:51:29 +09:00
cdrom
char Char/Misc driver fixes for 3.13-rc3 2013-12-08 18:47:25 -08:00
clk Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-11-15 16:47:22 -08:00
clocksource clocksource: arm_arch_timer: Hide eventstream Kconfig on non-ARM 2013-11-21 00:06:52 +01:00
connector connector: improved unaligned access error fix 2013-11-14 17:19:20 -05:00
cpufreq powernow-k6: correctly initialize default parameters 2014-01-06 15:52:49 +01:00
cpuidle cpuidle: Check for dev before deregistering it. 2013-12-03 22:05:22 +01:00
crypto crypto: talitos - fix aead sglen for case 'dst != src' 2013-11-28 22:25:17 +08:00
dca
devfreq
dio
dma dma: fix build breakage in s3c24xx-dma 2013-12-04 11:24:30 +05:30
edac sb_edac: Shut up compiler warning when EDAC_DEBUG is enabled 2013-11-30 12:26:36 +01:00
eisa
extcon extcon: remove freed groups caused the panic or warning in unregister flow 2013-11-26 15:17:23 +09:00
firewire [SCSI] Disable WRITE SAME for RAID and virtual host adapter drivers 2013-11-29 08:48:39 +04:00
firmware efi-pstore: Make efi-pstore return a unique id 2013-11-29 10:11:06 +00:00
fmc
gpio A rather big fix for a regression where we have dropped omap4 hwmod 2013-12-09 15:38:41 -08:00
gpu radeon_pm: fix oops in hwmon_attributes_visible() and radeon_hwmon_show_temp_thresh() 2013-12-15 12:16:00 -08:00
hid Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid 2013-12-13 13:21:28 -08:00
hsi
hv
hwmon hwmon fixes for 3.13-rc4 2013-12-12 11:05:19 -08:00
hwspinlock
i2c i2c: imx: Check the return value from clk_prepare_enable() 2013-12-12 22:48:22 +01:00
ide More ACPI and power management updates for 3.13-rc1 2013-11-20 13:25:04 -08:00
idle intel_idle: Fixed C6 state on Avoton/Rangeley processors 2013-11-28 14:35:26 +01:00
iio Fix build failure for gp2ap020a00f.c 2013-12-02 21:11:30 +00:00
infiniband Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2013-11-22 10:52:03 -08:00
input Input: adxl34x - Fix bug in definition of ADXL346_2D_ORIENT 2013-12-09 22:23:31 -08:00
iommu iommu/arm-smmu: fix error return code in arm_smmu_device_dt_probe() 2013-12-06 16:44:25 +00:00
ipack
irqchip Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-12-02 10:15:39 -08:00
isdn net: rework recvmsg handler msg_name and msg_namelen logic 2013-11-20 21:52:30 -05:00
leds leds: pwm: Fix for deferred probe in DT booted mode 2013-12-02 11:53:17 -08:00
lguest
macintosh powerpc/windfarm: Fix XServe G5 fan control Makefile issue 2013-11-27 11:35:47 +11:00
mailbox
md A set of device-mapper fixes for 3.13. 2013-12-13 13:22:22 -08:00
media [media] videobuf2-dma-sg: fix possible memory leak 2013-12-10 05:40:57 -02:00
memory
memstick tree-wide: use reinit_completion instead of INIT_COMPLETION 2013-11-15 09:32:21 +09:00
message drivers/message/i2o/driver.c: add missing destroy_workqueue() on error in i2o_driver_register() 2013-11-13 12:09:26 +09:00
mfd mfd/rtc: s5m: fix register updating by adding regmap for RTC 2013-12-12 18:19:26 -08:00
misc Char/Misc driver fixes for 3.13-rc3 2013-12-08 18:47:25 -08:00
mmc mmc: omap: Fix I2C dependency and make driver usable with device tree 2013-11-26 15:51:16 -08:00
mtd mtd: nand: pxa3xx: Use info->use_dma to release DMA resources 2013-12-12 15:02:04 -08:00
net igb: Fix for issue where values could be too high for udelay function. 2013-12-14 22:59:42 -05:00
nfc
ntb NTB driver bug fixes to address a missed call to pci_enable_msix, 2013-11-26 11:15:12 -08:00
nubus
of Merge branch 'for-linus-dma-masks' of git://git.linaro.org/people/rmk/linux-arm 2013-11-14 07:55:21 +09:00
oprofile
parisc
parport Kconfig cleanups for v3.13 2013-11-15 14:05:15 -08:00
pci Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-12-15 11:56:47 -08:00
pcmcia DeviceTree updates for 3.13. This is a bit larger pull request than 2013-11-12 16:52:17 +09:00
phy
pinctrl sh-pfc: sh7372: Fix pin bias setup 2013-12-03 10:38:41 +01:00
platform sony-laptop: do not scribble keyboard backlight registers on resume 2013-11-26 13:03:36 +09:00
pnp PNP: fix restoring devices after hibernation 2013-12-05 02:01:55 +01:00
power Highlights: 2013-11-18 15:35:09 -08:00
powercap PowerCap: Fix mode for energy counter 2013-12-05 02:05:48 +01:00
pps drivers/pps/clients/pps-gpio.c: remove redundant of_match_ptr 2013-11-13 12:09:35 +09:00
ps3
ptp
pwm
rapidio
regulator regulator: Fixes for v3.13 2013-12-13 11:39:54 -08:00
remoteproc
reset
rpmsg
rtc mfd/rtc: s5m: fix register updating by adding regmap for RTC 2013-12-12 18:19:26 -08:00
s390 s390/sclp: replace uninitialized early_event_mask_sccb variable with sccb_early 2013-12-02 15:31:07 +01:00
sbus
scsi SCSI fixes on 20131206 2013-12-06 08:30:18 -08:00
sfi
sh
sn
spi Merge remote-tracking branches 'spi/fix/bcm2835', 'spi/fix/bcm63xx', 'spi/fix/mpc512x-psc', 'spi/fix/mxs', 'spi/fix/pxa2xx', 'spi/fix/qspi', 'spi/fix/rspi' and 'spi/fix/txx9' into spi-linus 2013-11-28 11:31:35 +00:00
ssb
staging Staging: TIDSPBRIDGE: Use vm_iomap_memory for mmap-ing instead of remap_pfn_range 2013-12-03 09:42:45 -08:00
target Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2013-11-22 10:52:03 -08:00
tc
thermal Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-11-19 15:50:47 -08:00
tty n_tty: Fix missing newline echo 2013-11-29 12:53:19 -08:00
uio uio: we cannot mmap unaligned page contents 2013-12-02 11:50:37 -08:00
usb usb: hub: Use correct reset for wedged USB3 devices that are NOTATTACHED 2013-12-04 17:00:43 -08:00
uwb
vfio
vhost Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2013-11-22 10:52:03 -08:00
video Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc 2013-12-09 19:21:39 -08:00
virt
virtio Nothing really exciting: some groundwork for changing virtio endian, and 2013-11-15 13:28:47 +09:00
vlynq
vme
w1 drivers/w1/masters/w1-gpio.c: use dev_get_platdata() 2013-11-15 09:32:21 +09:00
watchdog sc1200_wdt: Fix oops 2013-12-10 08:48:15 +01:00
xen Bug-fixes: 2013-12-02 10:12:01 -08:00
zorro
Kconfig ACPI and power management updates for 3.13-rc1 2013-11-14 13:41:48 +09:00
Makefile ACPI and power management updates for 3.13-rc1 2013-11-14 13:41:48 +09:00