More Radeon Power Management Improvements

[Gaius]

Well, the code is open source, so you can reduce the number of pcie lanes yourself to find out. I played around with that a bit when power management was only in the user space driver and I did not find that reducing the number of pcie lanes resulted in lower power consumption, only to instability

FWIW I'm currently using fglrx at the moment and it's using all of the 16 pcie lanes with a HD 5750, regardless of the performance level.

I already did have a look at the code in radeon_pm.c but it is a bit too complex for me
So you mean, the PCIe lanes are not so important..that's interesting...maybe it is the algorithm used in the radeon driver that needs improvement

[bridgman]

...maybe it is the algorithm used in the radeon driver that needs improvement

What would you suggest, remembering that the PM code in the open source stack is perhaps 1/20th the size and complexity of the corresponding code in fglrx ?

[nanonyme]

What would you suggest, remembering that the PM code in the open source stack is perhaps 1/20th the size and complexity of the corresponding code in fglrx ?

I guess it's mostly about determining the absolute minimum settings on each card. Many laptop users would probably be perfectly happy with that? That's a rather tricky thing though if the card BIOS does not contain the absolute minimum settings. Should the driver still rely on them or ship with overrides users could manually enable?

[monraaf]

maybe it is the algorithm used in the radeon driver that needs improvement

In all honesty I don't really have any complaints about the power management in the open source radeon driver. It works like a charm for me with a HD 5750, so I don't see what exactly needs improvement.

System power consumption Idle Desktop:
-----------------------------------------
fglrx : 62 W
radeon: 65 W

GPU Temperatures Idle Desktop:
-----------------------------------------
fglrx: 40 ?C
radeon: 42/43 ?C


The only thing that I'm missing is something to manually control the fan, so I can make the thing just a little more quiet.

[agd5f]

The driver (open or proprietary) use the power state tables in the vbios. That's why they are there.

[Gaius]

In all honesty I don't really have any complaints about the power management in the open source radeon driver. It works like a charm for me with a HD 5750, so I don't see what exactly needs improvement.

System power consumption Idle Desktop:
-----------------------------------------
fglrx : 62 W
radeon: 65 W

GPU Temperatures Idle Desktop:
-----------------------------------------
fglrx: 40 ?C
radeon: 42/43 ?C


The only thing that I'm missing is something to manually control the fan, so I can make the thing just a little more quiet.

That's exactly my issue...it is not quiet at all most of the time...as it seems it takes too long to go back to normal speed...(more than 5 minutes instead of a couple of seconds). The problem is not the power consumption.

[darkbasic]

it seems it takes too long to go back to normal speed

Do you use profiles or dynamic pm?
Because dynpm is still experimental and should not be used.

[Gaius]

I use profile method.

[kernelOfTruth]

That's exactly my issue...it is not quiet at all most of the time...as it seems it takes too long to go back to normal speed...(more than 5 minutes instead of a couple of seconds). The problem is not the power consumption.

I approve of this post:

I regularly ramp up the fan (if for my taste the card is getting to warm - it's still summer after all ) and then after a short while turn it down to a pretty low frequency/rpm number where it doesn't annoy me

it would be really nice to have kind of a virtual "knob" to control how fast the fan turns

for my 5850 (with fglrx / catalyst) that's in general around 21-24%, so it doesn't have to be in explicit numbers

[tball]

I am wondering when dynpm is gonna be a stable solution. What difficulties are you facing with the vblank period and the power-state switching?