Root [Q] Question to Kernel Devs

[Mobstergunz]

Adreno 220 inside the MSM8660 or MSM8260 (1.2 GHz–1.5 GHz+1MB L2 Cache) with single channel memory. It supports OpenGL ES 2.0, OpenGL ES 1.1, OpenVG 1.1, EGL 1.4, Direct3D Mobile, DirectX 9.0c, SVGT 1.2, Direct Draw and GDI. (88M triangles/second, 2.4 Gpixels/second, standard clock speed up to 266 MHz, overclock up to 400 MHz).

Supposedly our GPU is capable of an overclock up to 400 MHz but the max i see in kernels made for the Evo 3D go to a max of 266 MHz for 2D and 320 MHz for 3D. My Question is can our phone achieve that 400 MHz Boost or will it cause trouble?

Edit: someone feel free to ask this on XDA aswell since the Devs there might not see this....

 

[gothicnerd1033]

Looks like I got ya kerneling now.. LOL

Good news. I managed to edit my own kernel
and compile it last night. Of course it is just basic tweaking for my first time. Now that I see how to do it.. Ill have one in no time.

 

[mrg666]

Supposedly our GPU is capable of an overclock up to 400 MHz but the max i see in kernels made for the Evo 3D go to a max of 266 MHz for 2D and 320 MHz for 3D. My Question is can our phone achieve that 400 MHz Boost or will it cause trouble?

Edit: someone feel free to ask this on XDA aswell since the Devs there might not see this....

Current overclock of 320 is simply editing two lines for the GPU clock and bus speed. I have tried the same method consistently for 366 and 400 as well. But the system is not able to use those clocks. At 366 and 400, everything works, no crashes, but the 3D clock does not go to max level, stays at the previous step of 266. So the end result is actually slower than 320.

CPU can have the ability but reaching a specific clock speed should be supported by the board (bus bandwidth, clock generator, voltage regulator). Either more involved software modification is necessary or the board does not support it; I haven't investigated. Maybe someone who has looked into this more extensively can chime in. This is what I know.

Edit: You made me curious. 366 and 400 pll clocks are not defined in the code let me add them and retry. I will post in my thread when I am done.

Edit 2:
I have defined the 400Mhz clock in clk_tbl_gfx3d array of arch/arm/mach-msm/clock-8x60.c as follows
F_GFX3D(400000000, pll2, 1, 2),

Now the kernel cannot boot with this defined. I will leave this here for now.

Edit 3:
For anyone who is wondering how to define additional frequencies in F_GFX3D(f, pll2, i, j)
f=(800000000*i)/j where f is the clock frequency, 800000000 is the base frequency, and i, j are multiplier and divider, respectively.

 

[SgtPropain]

Edit 2:
I have defined the 400Mhz clock in clk_tbl_gfx3d array of arch/arm/mach-msm/clock-8x60.c as follows
F_GFX3D(400000000, pll2, 1, 2),

Now the kernel cannot boot with this defined. I will leave this here for now.

Edit 3:
For anyone who is wondering how to define additional frequencies in F_GFX3D(f, pll2, i, j)
f=(800000000*i)/j where f is the clock frequency, 800000000 is the base frequency, and i, j are multiplier and divider, respectively.

I've been trying to find this equation for the past 3 weeks!! THANK YOU THANK YOU!!!

 

[Mobstergunz]

did some digging and it turns out the Adreno 225 runs at a Stock speed of 400 MHz it maybe be due to it being 28 nm tech

 

[mrg666]

did some digging and it turns out the Adreno 225 runs at a Stock speed of 400 MHz it maybe be due to it being 28 nm tech

In addition to previous generation process technology, architecture is also older. A225's come with Krait core (e.g. 8960) and, afaik, mostly dual-channel memory. Our 8660 with A220 is previous generation Scorpion core and single channel.