I already posted this in the Nexus dev forum, and I hate to clutter the boards, but I know that there are a bunch of talented devs here that may not see it on those forums. If we can bust the 30fps cap for good, and get the GPU overclocked, then we could see some serious gaming performance out of our Snapdragon devices.
I'm sure we all heard about being able to overclock the GPU on some of the old MSM devices, but the Snapdragon handles the graphics chip in a different way. The goal of this thread is to try and overclock the GPU on Snapdragon devices as well.
There is nothing GPU related in acpuclock-scorpion.c (the Snapdragon cpu clock settings) at least for setting gpu clock speed as far as I can tell.
In board-mahimahi.c (Nexus board file) and board-supersonic.c (Evo board file) there is some kgsl init code, but so far as I can tell it isn't setting the clock there, instead it seems to be pointing to PWR_RAIL_GRP_CLK to set the clock in both devices. It defines the variable in each of those files but I'm not sure where that variable is set, since it doesn't seem to be in any of the other board files as far as I can tell. I could be completely off here too though.
In drivers/video/msm/gpu/kgsl/kgsl.c there is a method called kgsl_clk_enable that seems to be called whenever the GPU is enabled. It looks like this:
The line that's been commented out is the original value, I replaced it with my value on the line below it in a failed attempt to overclock it. Probably a stupid effort on my part, I doubt it's that simple, but it was worth a shot. The comments at the end of the line are also my additions.
According to the clk.h files in the standard linux kernel, clk_set_rate is obviously a method to set the clock rate. The first variable is a struct that tells it which clock to set, and the second variable is a long value that is the rate you want it set at. Is it setting the right clock there for Snapdragon chips? Or is it only the clock for older chips?
I'm in way over my head with this source, I'm but a lowly Java dev, but I really wanna solve this. Can anyone with a little more experience than me throw in a little more info? Sorry if it doesn't make much sense, if it isn't clear just ask me & I'll try to explain a little more.
Regards,
Jesse C.
EDIT: Okay I did a little more digging and those kgsl settings should work for QSD8x50 chips. In the config file, under Drivers, Graphics Support, it allows you to enable 3D accelleration for QSD8x50 & MSM7x27 chips. The tag for that is CONFIG_MSM_KGSL_MMU. If you check in kgsl.c it checks to see if that is enabled in the config, and if it is then it compiles and uses kgsl.c & all of the kgsl code. That tells me that the clock is either not being set, or the wrong clock is being set. I'm adding some debug code right now so I can see in dmesg what code is actually being run.
I'm sure we all heard about being able to overclock the GPU on some of the old MSM devices, but the Snapdragon handles the graphics chip in a different way. The goal of this thread is to try and overclock the GPU on Snapdragon devices as well.
There is nothing GPU related in acpuclock-scorpion.c (the Snapdragon cpu clock settings) at least for setting gpu clock speed as far as I can tell.
In board-mahimahi.c (Nexus board file) and board-supersonic.c (Evo board file) there is some kgsl init code, but so far as I can tell it isn't setting the clock there, instead it seems to be pointing to PWR_RAIL_GRP_CLK to set the clock in both devices. It defines the variable in each of those files but I'm not sure where that variable is set, since it doesn't seem to be in any of the other board files as far as I can tell. I could be completely off here too though.
In drivers/video/msm/gpu/kgsl/kgsl.c there is a method called kgsl_clk_enable that seems to be called whenever the GPU is enabled. It looks like this:
Code:
/* the hw and clk enable/disable funcs must be either called from softirq or
* with mutex held */
static void kgsl_clk_enable(void)
{
//clk_set_rate(kgsl_driver.ebi1_clk, 128000000);
clk_set_rate(kgsl_driver.ebi1_clk, 245000000); // Looks like it sets the GPU clock, right? Wrong.
clk_enable(kgsl_driver.imem_clk); // Enable the clock
clk_enable(kgsl_driver.grp_clk); // Enable another clock, but why?
}The line that's been commented out is the original value, I replaced it with my value on the line below it in a failed attempt to overclock it. Probably a stupid effort on my part, I doubt it's that simple, but it was worth a shot. The comments at the end of the line are also my additions.
According to the clk.h files in the standard linux kernel, clk_set_rate is obviously a method to set the clock rate. The first variable is a struct that tells it which clock to set, and the second variable is a long value that is the rate you want it set at. Is it setting the right clock there for Snapdragon chips? Or is it only the clock for older chips?
I'm in way over my head with this source, I'm but a lowly Java dev, but I really wanna solve this. Can anyone with a little more experience than me throw in a little more info? Sorry if it doesn't make much sense, if it isn't clear just ask me & I'll try to explain a little more.
Regards,
Jesse C.
EDIT: Okay I did a little more digging and those kgsl settings should work for QSD8x50 chips. In the config file, under Drivers, Graphics Support, it allows you to enable 3D accelleration for QSD8x50 & MSM7x27 chips. The tag for that is CONFIG_MSM_KGSL_MMU. If you check in kgsl.c it checks to see if that is enabled in the config, and if it is then it compiles and uses kgsl.c & all of the kgsl code. That tells me that the clock is either not being set, or the wrong clock is being set. I'm adding some debug code right now so I can see in dmesg what code is actually being run.
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