Can someone anwer my kernal question?

Discussion in 'Samsung Galaxy Nexus' started by shanimal92, Dec 21, 2011.

  1. shanimal92

    shanimal92 Member

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    I have been running Zygot3 1.3 for a day now with the 1350mhz OV/UV kernel. It has been running like a champ; I even did a couple cpu bench scores to really push it for stability. Now i just flashed a rom with a 1400mhz OC/UV kernel but i couldnt run it. Not to say i ran it through it paces and too many FC and reboots, it just froze. My question is, did that extra 50mhz really push it over the edge that much, or is it just the difference in developer on the kernel?

    first rom and kernel:
    |ROM| ZYGOT3 1.3 | |12/14/2011| TK .4 CFS |12/20/2011| - RootzWiki
    [Kernel]AOSP LTE[3.0.13]UV/GPU+CPU OC/CIFS/SLQB/OTG(v0.0.4)[Dec-17] - RootzWiki

    second rom (couldnt find developer kernel post)
    http://www.droidforums.net/forum/gu...osp-4-0-3-cdma-gummynex-0-2-3-12-20-11-a.html
     
  2. Snow02

    Snow02 Active Member

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    Many phones can't run 1.4. Yes, that extra bump is just beyond where they're stable.
     
  3. shanimal92

    shanimal92 Member

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    Dang it! i read a while ago that the Nexus was stock underclocked from 1.5ghz, so it would easy to get them to 1.7 or something. i just thought since they were made to be clocked at 1.5, and just clocked slower to get better battery life, etc, then i would have a super phone running. Oh well, 1.35 is plenty fast for me and most everyone else. do you think, since it was underclocked, that could have done it? maybe, if the kernel allows me, i put the voltage back to normal would it work or does that really not do anything but limit the power it uses?
     
  4. Snow02

    Snow02 Active Member

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    Again, many of them won't run past 1.35. But like you said, it's plenty fast.
     
  5. Creed

    Creed Member

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    The chip can easily get to 1.5 GHz and higher, the clocking system that TI uses is dumb though. It clocks it 2.4 and then divides by 2. The phones doesn't know that though and it thinks that you are trying to clock it at 2.8GHz (1.4Ghz really...) and says, "hell no!" Although this is a problem for developers, it means that the phone thinks that the chip can run at 2.7GHz which is incredible. If you try to use TI's solution the Duty Cycle Correction (regular clocking e.g. 1GHz=1GHz) works UNTIL your system tries to conserve energy and under-clock (e.g. divide by 2) because switching clock methods crashes your phone.

    I dumbed it down quite a bit but you can read more: "Basically we've got a clock generator. For frequencies under 1GHz, you're supposed to run the "MPU DPLL" at double the desired speed and an internal clock divider will bring that down by 1/2, so we're running the DPLL at 2GHz at 1GHz and 2.4GHz at 1.2GHz. For 1.5GHz we would need to run the MPU DPLL at 3GHz, which is where we run into problems - it simply doesn't want to go that high on most peoples' devices.

    TI's solution to this was a feature called Duty Cycle Correction, which is needed to use the frequency without a 1/2 divider, making it so we only have to run the MPU DPLL at 1.5GHz to run the MPU at 1.5GHz. But this revision of the 4460 has a major bug where switching DCC off (to switch to lower frequencies) causes crashes. This makes DCC utterly useless, so we're kind of stuck here.

    GPU speed is independent of CPU speed as far as I can tell. And the stock with voltage control kernel in the OP does have the 384MHz GPU overclock applied."


    Source: [DEVS/KERNEL] Galaxy Nexus 1.4GHz overclock + Undervolting patches - Page 4 - xda-developers

    Post 38.

     
  6. shanimal92

    shanimal92 Member

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    pardon my ignorance, but does this mean that eventually a developer could make a kernel that will let every phone run at 1.5; since it is underclocked my default?