Questions about power, clocks, voltage

[alfazaz]

Hello !

I came recently to the open-source driver for my ATI V5200 FireGL video card because fglrx is not ok with it and mandriva 2009.1.

Firstly, thanks to the developpers for improvements of this opensource driver (since my last try) !

I would like to have a greatest battery life (quite like with the low voltage powerstate with fglrx and aticonfig). The Option "ForceLowPowerMode" "on" is set in my xorg.conf but it seams to adjust only the engine clock of my card.

So, I made a change to radeon_pm.c :

------
if (info->IsAtomBios) {
atombios_set_engine_clock(pScrn, info->pm.mode[i].sclk);
/* Add to change also memory clock */
atombios_set_memory_clock(pScrn, info->pm.mode[i].mclk);
/* End */
} else
------

and now, I can play with lowest Memory Clock (and it works). But this raises a question : why the developpers didn't make the change ok for mclk ? I made a mistake ?

Last questions : In atombios.h, I can read

#define ATOM_PM_MISCINFO_POWERPLAY_SETTINGS_GROUP_MASK 0x70000000L //1-Optimal Battery Life Group, 2-High Battery, 3-Balanced, 4-High Performance, 5- Optimal Performance (Default state with Default clocks)

Is it possible to have the 1 choïce (Optimal battery life group) ? Is it possible to lower the voltage of the video card (like on fglrx) ?

Sorry if my questions are too "simplist" but I'm far from being a programer (and my english is poor...).

Thanks in advance for replies

[agd5f]

Power management is, in general, tricky to get working well in all cases. At the moment we are trying to make sure we get the bugs worked out of engine clock changes before adding mclk support. Changing the memory clock is also trickier than the engine clock in that you need to make sure you have enough memory bandwidth available to feed all the active memory controller clients (1 or 2 display controllers, 3D engine, 2D engine, etc.). It should generally work however.

Adjusting voltage on cards where it is supported is also possible, but I haven't had time to work out the sequences yet.

Power management should get much better once we move to kms as that will give us the full view of the hw and allow for much more dynamic capabilities.

[alfazaz]

Tnahk you for your reply !

[alfazaz]

After one day of test with an low value of mclk (the same as fglrx lowest mode), I saw only one bug : I cannot switch to console with Ctrl+Alt+F1 (freeze).

But the system works great with two displays... And the GPU is 10 degrees coldest than before. :-)

[esodax]

I made the same changes as alfazaz to set the mclk, then added the ForceLowPowerMode option to xorg.conf, but how do I verify that it actually worked.
Is there a way to check the current clock speed?

glxgears dropped not more then ~2 frames after the change, makes me wonder if it's really working.

My card is the Mobility HD 3650.

[agd5f]

I made the same changes as alfazaz to set the mclk, then added the ForceLowPowerMode option to xorg.conf, but how do I verify that it actually worked.
Is there a way to check the current clock speed?

glxgears dropped not more then ~2 frames after the change, makes me wonder if it's really working.

My card is the Mobility HD 3650.

The OpenGL 3D driver for your card is not complete yet so gears is using software rendering so the engine or memory clocks shouldn't have much effect.

[esodax]

That explained it.
Thank you.