The code is already included in 2.6.35. See this post for more information on using it:
Note that there is also now a "mid" profile.
I am pretty sure Linux 2.6.35rc4 has the latest PM functions integrated.
If I wanted low profile to be used by default on boot, what would be the preferred location to set it?
Beyond the flicker, is there any downside to frequent reclocking? Shortened hw life?
FYI, some power consumptions tests (KMS, Xorg with radeon driver from yesterdays git snapshot, one head enabled, no relevant CPU load):
low: 100..103W (pretty close to normal idle state with fglrx)
low (with both heads enabled): 118..121W (also close to fglrx w/ multihead)
My naive conclusion is that "auto" mode is not aggressive enough or doesn't get enough information to control efficiently. But I am sure you know better.
If you're thinking of the HDD lifetime issues with the power management in some Linux configurations that come up a few years back, remember that those things have complex moving parts, and it was the strain on those which led to their decreased lifetime, not the electronics.
Power management makes the hardware live longer, not shorter. HW life is shortened when you don't use PM.
Yep. The power management code only programs non-permanent registers - there's no writing to non-volatile memory or anything that would detract from lifetime. The proprietary drivers also dynamically reclock the chips.
No it doesn't, my desktop board BIOS doesn't support thatYou should hope not, your CPU is doing it constantly too.
No speedstep or C states beyond C1.
Does 2.6.35-rc4 support undervolting? Can it show gpu temperature?