[KERNEL] [2012-01-12] V2.0 FM Kernel based on 2.6.35.14 [Beta]

still waiting for latest update~~

I'm sorry for asking it again but how can I enable adb features such as shell, logcat, etc?
It just doesn't recognize my device with your kernel.

Thanks a lot.

upd: sorry, it magically started working as it should

Thanks for this kernel. BTW does anyone have problems with stock music player with this kernel ?
When I switch to music player using 'recent' it starts currently playing song from the beginning. Double pressing call receive button of the headphone does not play next song.(I use samsung headphone which I got with galaxy ace).

It does not reduce Android OS battery usage at all - 2.6.35.12 only hides it.

http://git.kernel.org/?p=linux/kerne...9c081a2e6dd9da is the one that makes Android OS battery usage disappear from Settings->About->Battery Usage (How do I know? git bisect is your friend!)

As you can see, that is only an accounting/reporting patch - it doesn't change the amount of time spent in interrupt handlers during suspend/resume at all, nor does it affect the amount of battery used during suspend/resume.

Best example, one can cause frequent resume/suspend cycles which shoot AOS through the roof as follows from a Linux machine:
You will see that whether you are on .7 or .14, battery drain will be the same, but the percentage of AOS usage reported will be MUCH lower on 2.6.35.12 and above.

Edit: Also, as far as implementing 100 MHz and 50 MHz, I strongly suggest you read section 6 of the paper on idle states (clock/power gating) that Ezekeel links here - http://forum.xda-developers.com/show...1431105&page=9

You are right. I had written it somwhere in the thread here. But it looks better.

Unfortunately I'm using another "posts per page" setting, therefore I'm not able to find this post.

Bluntly, it describes in incredible detail why anything below 200MHz can actually cause things to go slower and use MORE power.

As an imperfect example, the power required for 100MHz is 90% of the power required for 200MHz. So, let's say 200MHz uses 1000mv - meaning that 100MHz uses 900mv. For the processor to run a given process for 1000ms at 100MHz would take MORE power than the processor to run the same process for 800ms at 200MHz and then be in an idle state for 200ms.

Non-engineering language: on the exynos processor, because of the voltage curve, using 50 and 100MHz actually causes a higher battery drain.

Here's a direct link to the PDF document at IBM: http://www.research.ibm.com/arl/proj...ling-final.pdf

It's actually a fairly interesting read (as long as you don't have any distractions.)

Take care
Gary

Ah... Next time I won't link based on page. garyd9 linked to the paper in question.

The basic idea is that the classic rule of power usage being linearly proportional to clock speed becomes invalid when the CPU can shut off the clock when not in use. It goes completely out the window when the CPU can shut off core power when not in use.

At a minimum, our device has the ability to shut off the core clock when the CPU is idle. As a result, if something takes 90% of the CPU at 100 MHz and only 45% at 200 MHz - these tasks will at best take the same amount of total power, since the CPU is clock-gated 10% of the time at 100 MHz and 55% of the time at 200 MHz. If the voltages for these frequencies are the same, this means no power savings.

However, in addition to basic clock gating, the CPU has deeper idle states (look in arch/arm/mach-s5pv310/cpuidle.c ) that allow it to completely shut power off to the core. In addition to dynamic power consumption (dependent on clock rate), all CPUs have some level of static power consumption (dependent only on time, even if the clock is stopped). Basic idle doesn't affect static power, however, deeper idle states such as LPA and AFTR do, as the CPU can completely shut off power to parts of the core.

Once power gating comes into play - if 100 MHz and 200 MHz use the same voltage, 45% load at 200 will use LESS power than 90% load at 100, due to the CPU hitting LPA or AFTR idle states during the 55% idle time.

Also - if you start looking into idle states you may come across Ezekeel's Wheatley governor for the Galaxy Nexus. Be warned that due to differences in the way idle states are handled between the OMAP4 and the Hummingbird/Exynos, Wheatley will NOT work as it was designed on Hummingbird or Exynos CPUs.

do you mean that if both 100mhz and 200mhz use the same voltage (850mv in my case) then running on 100mhz consumes more power since things take longer to run.
would it be the same for 200mhz and 500mhz too because they too run on the same voltage for me.

Interesting and enlightening article Entropy512. I noticed that 100mhz, 200mhz and 500mhz frequencies on GNote have same voltage. So it would be better clock the cpu between 500 and 1600/1700 and undervolt. How silly! I always thought that running cpu on min freq would save battery. Running it at 100mhz would rather consume more battery as it takes more time to finish a task.

I fail to give the respecive source to that information, but I believe with higher clock speeds efficiency also declines. So while 200MHz has almost about twice the output of 100MHz, 500MHz does not have the same relative increase in output as the increase in clockspeed is vs. 200MHz. This is due to waste, for example in conductor loss, heat loss etc. Also take into consideration that the bus frequency gets upped at 500MHz from 133 at lower speeds to 266MHz at 500MHz and upwards. So basically my answer - scientifically unfounded - is no, 500MHz does not result in a relative better power consumption situation vs. 200MHz solely based on same voltages. I'll see if I can back up this claim somehow.


#Tapatalk #Galaxy Note