[PATCH] As-close-to-stock-as-possible kernel defconfig

---

Attached is a patch against the E4GT open source release (SPH-D710_Opensource.zip) containing defconfig changes necessary to get a source-built kernel that's as close to stock EG30 as possible. Also attached is a source-built test kernel that attempts to be indistinguishable from EG30 (hopefully same LoS behavior, unrooted, etc.). I've posted this before, but now that it's been tested (at least by daneurysm, thanks!) I figured it was worth making a dev thread so it would have better visibility to the folks most interested in it.

The purpose of this patch is to enable folks to build kernels nearly-identical to EG30, so as to serve as a proper starting point for custom kernel development (admittedly, a good deal of which has already happened). Since it's just kernel config changes, I welcome kernel developers to compare this against your own configs and make any changes you feel appropriate.

Background:

Compiling a kernel from the E4GT kernel sources with the shipped defconfig yields kernel builds that differ quite significantly from EG30. Among the differences, many folks have reported undesirable effects, such as exacerbation of loss-of-signal and other problems. There already exists efforts (e.g., LoStKernel) aimed at eliminating problems like loss-of-signal, but it's a common frustration among developers that what Samsung released as "EG30" sources appear bizarre, if nothing else.

A few weeks ago I posted an inconclusive initial analysis of the source situation, and followed up more recently with an attempt to eliminate all the defconfig changes in the source release in order to either get a kernel as close to stock as possible, if not prove that the kernel source release is bungled.

At this point, I'm uncetain if the source release is actually EG30 or not, aside from that the kernel configuration is definitely not EG30's (which this patch attempts to correct), and there may be some additional modifications to the Westbridge driver. As for the kernel config changes, unmodified source-based kernels include a good deal of debugging options (performance events, profiling support, tracepoints, debugging for preemption, mutexes, spinlocks, etc.) that touch enough of core kernel behavior to plausibly account for the problems folks observe in source-based kernels.

I know chris41g has indepenently implemented a fair number of these kernel config changes already, perhaps exactly those that exacerbate loss-of-signal. Still, for anyone interested in development that wants to "start with EG30 and go from there", this patch may well be of use.

Mirror links:
EG30 fix_defconfig patch: fix_defconfig.diff
Source-compiled, EG30 kernel: kernel-opensource-1.tar.md5

LoStKernel Exp has these changes, thanks mkasick

big ups man, i hope this gets more attention so that more dev's feel comfortable developing aftermarket kernels.

"Sorry, you are limited to 5 thanks a day"

2 days in, running perfectly and so far no LOS at all, which is on par with the stock kernel.

Excellent work, thanks for the effort.

Sent from my SPH-D710 using XDA App

Thanks for this. Will come in handy.

Sent from my SPH-D710 using Tapatalk

Thank you sir! Anyone posting anything development wise for a good base is always welcome and appreciated. Hope Samsung provides and good fix for our next base.

Properly thanked

Originally Posted by xlGmanlx

big ups man, i hope this gets more attention so that more dev's feel comfortable developing aftermarket kernels.

"Sorry, you are limited to 5 thanks a day"

Update: 3 Days running, no LOS and nothing strange happening. Phone is running great. Battery performance is as good as stock, LOS occurance appears as good as stock (like I said, 3 days in and I've seen exactly zero). No strange foreclosures or fruit loops. No funny business at all. On any previous kernel I definitely would have had multiple LOS events by now.

I think you cooked up a winner.

Glad to hear. Thanks for testing it.

Originally Posted by mkasick

Glad to hear. Thanks for testing it.

Mkasick as usual your contributions and knowledge are top notch

Sent from my Nexus S 4G using xda premium