[Q] Kernel Question - Nexus 7 Q&A, Help & Troubleshooting

While I've flashed a good share of ROM's on my Droid X in the past, it had a locked bootloader. As such, I never really learned much about custom Kernels.
Unlike the stock ROM for the Droid X, I'm very happy with the stock ROM on the N7.
I'm unlocked, and rooted on the N7, and very happy with how it performs.
Is there something I'm missing out on? I don't care about OC'ing it, because it's plenty fast. UV'ing it would be nice, but is there a good app that would do that for me, without having to mess around data wipes, and possible incompatibilities when updates are released?
Basically, I read through a bunch of the kernel posts, and aside from over clocking, or under volt'ing, I'm not sure I understand all the hype. I mostly see people saying that one kernel causes problems with certain ROM's, and another one causes other issues, and another works great with a certain custom ROM. Is there some really big performance gain, say in wifi range, or battery life, from any of these to make it worth the bother?
The only things I really care about are wifi range, battery life, and gps strength. Honestly, all of those are already really good just on stock, but I can't think of any real flaws, so nudge me in the right direction, if you would.
Are custom kernels worth it for someone like me? Are there good root apps that improve wifi reception range a bit, or extend battery life a tad, or speed up gps acquisition a little? Would a custom kernel do any of that anyways?
Regards,
--bb
// I should mention that I'm on 4.2.1, the HSPA+ model (but don't frequently use the cell connection).

bladebarrier said:
While I've flashed a good share of ROM's on my Droid X in the past, it had a locked bootloader. As such, I never really learned much about custom Kernels.
Unlike the stock ROM for the Droid X, I'm very happy with the stock ROM on the N7.
I'm unlocked, and rooted on the N7, and very happy with how it performs.
Is there something I'm missing out on? I don't care about OC'ing it, because it's plenty fast. UV'ing it would be nice, but is there a good app that would do that for me, without having to mess around data wipes, and possible incompatibilities when updates are released?
Basically, I read through a bunch of the kernel posts, and aside from over clocking, or under volt'ing, I'm not sure I understand all the hype. I mostly see people saying that one kernel causes problems with certain ROM's, and another one causes other issues, and another works great with a certain custom ROM. Is there some really big performance gain, say in wifi range, or battery life, from any of these to make it worth the bother?
The only things I really care about are wifi range, battery life, and gps strength. Honestly, all of those are already really good just on stock, but I can't think of any real flaws, so nudge me in the right direction, if you would.
Are custom kernels worth it for someone like me? Are there good root apps that improve wifi reception range a bit, or extend battery life a tad, or speed up gps acquisition a little? Would a custom kernel do any of that anyways?
Regards,
--bb
// I should mention that I'm on 4.2.1, the HSPA+ model (but don't frequently use the cell connection).
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I am using stock as well but I'm using the M-Kernel. Pretty good battery life and good on performance too. You should give it a try.

Thanks for the suggestions. I guess I'll just jump in and experiment with those.

A custom kernel won't do any of the 3 things you listed, extend WiFi, speed up GPS, improve battery life. I've tried most of the kernels available for the nexus 7 and only use a custom (omega) because It slightly smooths out a couple games I play daily. Battery life has never increased under the same usage for me, though some kernels did decrease battery life.
Sent from my Galaxy Nexus using xda premium

95Z28 said:
A custom kernel won't do any of the 3 things you listed, extend WiFi, speed up GPS, improve battery life. I've tried most of the kernels available for the nexus 7 and only use a custom (omega) because It slightly smooths out a couple games I play daily. Battery life has never increased under the same usage for me, though some kernels did decrease battery life.
Sent from my Galaxy Nexus using xda premium
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Gotcha, thanks for the response. I'll skip it then. It sounds like I'm not a good candidate for such things.

95Z28 said:
A custom kernel won't do any of the 3 things you listed, extend WiFi, speed up GPS, improve battery life. I've tried most of the kernels available for the nexus 7 and only use a custom (omega) because It slightly smooths out a couple games I play daily. Battery life has never increased under the same usage for me, though some kernels did decrease battery life.
Sent from my Galaxy Nexus using xda premium
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I didn't do any extensive battery life tests on the stock kernel, but after flashing motley I compared stock voltage to undervoltage (both while overclocked), and undervolting gave significant improvements.
OP, you mention you're happy with the performance at stock, but I'd give overclocking a try anyhow. My N7 was snappy to begin with, but after overclocking, it's insane.

Related

So what kernel do you tend to have better battery life with?

I've always had problem with the CM kernel, so I switched to wildmonk's and I have to say I've had some improvement, even though I believe its more voltage.
How is everyone else's battery on which kernel? Just curious on which ones I can squeeze the most out of.
oh geez...
I'm using the kernel that comes with CM, but I've got SetCPU installed and set to lower the CPU speed when the screen is off. Seems to make a world of difference.
If you don't already have SetCPU, I highly recommend purchasing it.
The stock kernel of CM 6.1 is pretty good itself. The Wildmonks ones are excellent though. However, you will need to use applications for root users like:
SetCPU - To configure CPU speed. Set the profiles properly. Otherwise, it's no good
Spare Parts - To determine which application(s) use more power, CPU and Data
DroidWall - To configure which apps are allowed to access the internet and when
Apart from these you may use various rendering effects found in CyanogenMod Settings for reducing the brightness of the screen
Please keep in mind there are a lot of other factors that affect battery life rather than just the kernel. Usage and configuration are two HUGE factors that a lot of people seem to forget about. Battery usage will also vary between ROM builds, software installs, radio firmware versions, network availability (weak vs strong signals), and even minute hardware differences.
Just because something works for one person doesn't mean it will work for everyone. Your mileage WILL vary.
Personally, I've gotten good results with WMs kernels, Kangorama ROMs, the 5.08 radio, and a couple of software tweaks (SetCPU, JuiceDefender + JuicePlotter to view usage trends, and Tasker with Brightness/Wifi/Location profiles).
codesplice said:
Please keep in mind there are a lot of other factors that affect battery life rather than just the kernel. Usage and configuration are two HUGE factors that a lot of people seem to forget about. Battery usage will also vary between ROM builds, software installs, radio firmware versions, network availability (weak vs strong signals), and even minute hardware differences.
Just because something works for one person doesn't mean it will work for everyone. Your mileage WILL vary.
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That may be true, but that doesn't mean that the kernel can't have a huge impact on the battery life, especially if the kernel lacks optimization. There are only so many things that the kernel itself can do to improve battery life, but there are tons of things it can do to worsen battery life. Personally I have been pretty prudent on managing my phone's battery through various apps and tweaks, and was really disappointed with the stock CM 6.1.1 kernel, as it pretty much seemed like it was ignoring or overpowering all my tweaks.
After only about two hours of sitting idle with the screen off, I could lose as much as 30% of my battery, whereas with older ROMs I could have my phone unplugged for about 10 hours with minimal use, and only lose about 15% battery. I was running the exact same apps and settings as in CM 6.0, and I had been sitting at home in the same room the whole time, without any noticeable changes in network signals. Switching to Wildmonk's kernel immediately brought my battery life back to normal, and I doubt that it was merely coincidence, especially after flashing to a nandroid backup of (mostly) stock CM 6.1.1 made the battery problems come back.
Based on my recent experience, I wouldn't rule out the possibility that the kernel can make noticeable improvements. If you can rule out network problems, display settings, and most of your software tweaks, then the kernel is the only thing left to check.
earlyberd said:
Based on my recent experience, I wouldn't rule out the possibility that the kernel can make noticeable improvements. If you can rule out network problems, display settings, and most of your software tweaks, then the kernel is the only thing left to check.
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Absolutely, but the kernel is not the ONLY variable that affects battery drain. A lot of people are quick to blame the kernel, and then are shocked to find that they have crappy battery life on all kernels because they haven't changed their ROM/radio/settings/usage/configuration.
wildmonk kernel has been great for me. i tried a bunch of them..but i settled on
2.6.35.4-925mv-cfs-svs-aix-720p-monks-082710
the recent ones tend to drain the battery when wifi is enabled. the android system process seems to be in use. normally it doesnt hit above 10%, but with the latest, it goes to 40%

[Q] Bulletproof ROM/Kernel Combo?

I love to play around with new ROMs and kernels and usually don't mind a few hiccups and occasional poor performance. But soon I will have a one week period where I need my phone to be as solid as possible. What's the best ROM/kernel for this?
I currently use CM7 as my daily and have tested CM9. CM7 is great except battery life is pretty bad, with both the CM7 and Samurai kernels. I lose about 1% of battery for every 90 secs I'm actively doing something - even on Wifi and with a strong 3g signal. A 15minute drive with GPS (and screen off) easily takes 10% off my battery. This is unacceptable for my upcoming event.
I would like a ROM/kernel combo that can go for a minimum of 12 hours with moderate use. No voice, but frequent texting, email, twitter checks, some photos, and calling up pdfs. Battery life and stability are the top concerns, but GPS is important as well. CM7 gives me the best GPS results I've ever had with my Epic, but like I said, the battery performance is awful.
Any ideas? Focusing on all the cutting edge stuff means I've lost touch with the latest improvements on the more basic, but more solid ROMs.
Thanks!
get a larger battery or pick up a spare oe battery as a backup.
this is one of those questions you just dont ask cause it all depends on how you use your phone and all that i know you say what you mostly use it for but it still doesnt help if you are looking for a stable rom as far as mtd goes they are all good and as far as kernels go they are all good but the kicker is just finding what works best for you feel free to play around with them flash one per day and figure out which one works best for you cause honestly we cant tell you cause what would extend our battery life might not work for you because you use your phone differently than we do but trust me all of our devs are gonna throw out something that doesnt work all the warnings are there and all the help and how to's for each rom and kernel are in their respective threads sorry i couldnt give you a better answer bud
happy flashing
Oh and I forgot to mention since you have been running cm7 make sure you don't flash a bml rom not sure if u were aware of that or not so only flash and MTD rom and kernel
CleanGB. No OC/UV, and buy an epic touch 1800mah battery. For me I get best responsiveness vs battery life if I run 100/800mhz with governer set to performance. You'd have to REALLY try to kill that battery in a day with this setup.
Edit: you use gps in the car without plugging it in? No wonder your battery commits suicide lol. If I use gps and stream music through bluetooth it still discharges on the charger.
There is no such thing. Even pure stock has errors on some people's phones. You need to try one or if it is that important than stock is your best bet. EVERY Phone is different. Read through some of the ROMs...95% of the people have no problems and 5% do. It is the nature of the beast. No one can tell which is best for YOUR phone. And if CM7 is giving you terrible battery life, there already is something wrong with your phone setup. You probably need to start from scratch and restore no apps or data and download apps fresh from the market.
I've always had good luck with CleanGB roms & kernals by toadlife.
joedig52 said:
I've always had good luck with CleanGB roms & kernals by toadlife.
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But not everybody does. There is no best. I can easily say marcusantrom with shadow kernel is best on touchwiz and CM7 with the kernel it comes with is the best in general. I won't say this because different people have different phones and preferences... if you really want the best rom/kernel/theme, make it yourself.
In Soviet Epic forum, clockworkmod root you!

[Q] Best Battery life. Stock or Custom?

experienced user told me that Stock(AOSP 4.2.2) is better than Custom (CM10.1, AOKP...) (in terms of Battery life.)
is this true? maybe someone test?
i have Nexus 7 3G (AOKP off + franco Kernel)
It's impossible to give you a truly correct answer because there's too many variants which can make battery life differ.
As things like apps, usage, ROMs, kernels, mods, the device, tweaks and many other things can all have different effects on battery life, it really is dependant on the specific situation.
So if I was to have the 3G model (as you have), be using the same ROM and kernel combination, have all settings exactly the same, have exactly the same apps installed, use the apps for exactly the same amount of time and have the same mods/tweaks installed, we could still quite easily have our battery life last a different amount of time.
Due to that, that's why it's always best to just test them out for yourself so then you'll know exactly how your battery will perform in regards to your usage
Sent via my HTC One using XDA Premium
The ROM makes little to no difference whatsoever. Battery life is more affected by the kernel and your own individual settings.
Sent from my Nexus 7 using Tapatalk HD
But some ROMs claim to have better battery life than the others (CodenameBattery, SuperCharge Series). Are they talking nonsense?
Sent from my Nexus 7 using xda premium
Odp: [Q] Best Battery life. Stock or Custom?
I use stock 4.2.2 rooted in two weeks now, and the battery is very good. Try to stick to stock in one week or so.
Sent from my Nexus 7 using XDA App
StrangerWeather said:
But some ROMs claim to have better battery life than the others (CodenameBattery, SuperCharge Series). Are they talking nonsense?
Sent from my Nexus 7 using xda premium
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Some could absolutely be talking nonsense but others could actually be telling the truth.
They could have certain tweaks in place that will indeed improve battery and could also have more power saving apps included. There's so many variables that without actually testing them out for yourself, there's no way of knowing whether it will have better battery life or not.
I use a custom ROM on my gnex simply for color control, but in my experience custom kernels never improve battery enough to make more than a very minimal difference. I stick to stock with my 7 for multiple reasons, one being certain EA games won't download data while using custom kernels. You'll see people claiming custom kernel's get them 9 hours display time ect... Well I've gotten that on stock depending on what I was doing with my 7. My average is usually more like 5-6 over 2-3 days as I use it more for gaming than anything.
Sent from my Nexus 7 using xda premium
Like previous members have stated, it's not possible to give you a definite answer as to which gives you better battery life. When I received my N7 I rooted and installed a ROM and a kernel. Ultimately I revert back to full stock android for many reasons. One, battery life was much better on stock kernel than a custom one. I didn't need a custom ROM either. Only on my N4 would I need custom software installed because recently my mother has been using my N7 a lot so my N4 is what I use most now.
Sent from my Nexus 4 using Tapatalk 2

[Q] Which ROM/Kernel is the best for me?

Hey guys,
I think I read somewhere that threads like this are not really wanted here? So I'd like to clarify first, I'm looking for certain aspects and not for "the best" rom or whatever. If there's more than one which would meet my criteria, feel free to just name all without any opinion to it
There are just so many roms and kernels and I'm having trouble finding information what they can and cant do...Sometimes it's just a download link and thats it!
I will be travelling with my Nexus 10 and would like to use an internet dongle via USB OTG to access mobile internet in the various countries and I would like to use OTG for storage (usb sticks i guess).
Also it should be stable/fast and I would like to somehow prolong battery life (UC/UV? Dont know anything about that yet but I guess that would be how?), just in case I won't be near a power outlet for a couple of days.
I don't really care too much about design, so minimalistic is best!
Which kernels can I use? Does the rom even matter? are there certain roms that seem to work best with the kernel I would need?
Thanks for any help!! I will get the tablet the day after tomorrow so it'd be awesome to have some information so that I can root and start trying stuff out immediately=)
If you seek stability then go for CleanRom and aosp+ kernel. As for battery life there isn't anything magic out there, just turn the WiFi off when you can.
UV doesn't help, no matter what you will be told, it's just placebo.
I've used mrRobinsons AOKP PUB ROM + Ktmanta kernel for the last 2 months. Just took it on a long trip, used a 32gb USB OTG just fine. I watched several movies and had great battery life. Performance is awesome too.
No experience with an internet dongle, sorry. I just use the hotspot function from my phone.
lvnatic said:
If you seek stability then go for CleanRom and aosp+ kernel. As for battery life there isn't anything magic out there, just turn the WiFi off when you can.
UV doesn't help, no matter what you will be told, it's just placebo.
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It bothers me when someone says that such and such is the only stable combination, it obviously isnt or no one would ever run anything else. I have never had problems when I ran AOKP, or when I used to run CM10, or running on Rasbean which is based on AOSP. Each kernel can have certain releases that have issues, just as Craig's AOSP+ kernel could at some point, but not every release has always or will always be unstable. To my knowledge only Franco's R12 has issues right now and all other kernel releases are fine. Franco's R11 is perfectly fine too.
Also I can both mathematically prove undervolting can save battery and can show you plenty of people with actual experience on it saving battery. So you should really stop going around and spouting off "facts" which are completely untrue. But you are right about there being no magic stuff, it is all science.
I get wonderful battery life daily using KTManta and a tweak of the CPU/GPU. But then, my tweak stops doing so well if I use a CPU intensive app like FL Studio. I can go about 12 hours or more and still have 30-40% of battery left, with off-and-on usage all day including some gaming. Extended gaming (I'm talking Asphalt 7, Shadowgun, not Plague Inc) will murder that, but that's what I set up my CPU/GPU to offset.
Also completely stable with RootBox ROM (or CM10, or AOKP, etc) so long as I don't try "hotplugging"

[Q] ROM with the best battery life?

Exactly what the title says. I've been looking here and there for some ROMs that I would like to flash and I found quite a number of them to try out. However I want to hear from the experts who have been flashing custom ROMs all the time. What would you say would be the best ROM on battery life? I am currently running Hyperdrive RLS21 and I'll say it does decent on the battery life albeit the standby time can improve (I lose around 10% in a night if I leave it 100% uncharged).
RawSynergy said:
Exactly what the title says. I've been looking here and there for some ROMs that I would like to flash and I found quite a number of them to try out. However I want to hear from the experts who have been flashing custom ROMs all the time. What would you say would be the best ROM on battery life? I am currently running Hyperdrive RLS21 and I'll say it does decent on the battery life albeit the standby time can improve (I lose around 10% in a night if I leave it 100% uncharged).
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Click to collapse
First off battery life is subjective and usually has very little to do with the ROM. It is the kernel and settings which usually have most affect on battery life amongst the same user. This is not something you can compare from user to user but must be compared by the same user under the same conditions.
Let me give you some examples..a heavy gamer will get vastly different battery life from a heavy phone/text user. A person in low signal areas that has many apps synching will get horrible battery life compared to someone who has very little apps or great signal. I think you get the idea.
Kernel settings such as governor/scheduler/OC/UC choices will vastly affect your battery life. You really either need to compare ROMs yourself, or find someone that has compared ROMs under the same situation and similar use as you to get any useful data. I see that you asked for opinions from those flashing many ROMs. Other factors can affect that too...were they all clean flashed? Were any adjustments made?
Hope this helps! And hope you find the perfect ROM for you! Happy Flashing!
KennyG123 said:
First off battery life is subjective and usually has very little to do with the ROM. It is the kernel and settings which usually have most affect on battery life amongst the same user. This is not something you can compare from user to user but must be compared by the same user under the same conditions.
Let me give you some examples..a heavy gamer will get vastly different battery life from a heavy phone/text user. A person in low signal areas that has many apps synching will get horrible battery life compared to someone who has very little apps or great signal. I think you get the idea.
Kernel settings such as governor/scheduler/OC/UC choices will vastly affect your battery life. You really either need to compare ROMs yourself, or find someone that has compared ROMs under the same situation and similar use as you to get any useful data. I see that you asked for opinions from those flashing many ROMs. Other factors can affect that too...were they all clean flashed? Were any adjustments made?
Hope this helps! And hope you find the perfect ROM for you! Happy Flashing!
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Click to collapse
Problem is that I'm on a locked bootloader (ATT variant) so it's only natural that I should ask for a ROM that could give the best battery life since I can't flash any kernels
I'm no expert but I've been flashing ROMs for my S2, now my s4 for last 3 years. I've found recently that Tesla has the best battery life, 4% drain over 8 hrs at night. Best ever

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