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Recently, I've been running Linux built from the drm-next-3.11 branch and it works quite fine.

However, I'm intrigued by the fact that my card supports two voltage levels, 1000 and 1200, and yet the power management operation does not scale the voltages but only only power levels with different engine clocks, mainly 720MHz and 300MHz.

At idle, debugfs reports this:

uvd    vclk: 0 dclk: 0
power level 0    sclk: 30000 mclk: 50000 vddc: 1200

I'm wondering whether the default voltage (vddc) is supposed to be 1000?

Additionally, log messages show this in particular:

kernel: switching from power state:
kernel:         ui class: performance
kernel:         internal class: none
kernel:         caps: single_disp video 
kernel:         uvd    vclk: 0 dclk: 0
kernel:                 power level 0    sclk: 22000 mclk: 25000 vddc: 1000
kernel:                 power level 1    sclk: 30000 mclk: 50000 vddc: 1000
kernel:                 power level 2    sclk: 72000 mclk: 50000 vddc: 1200
kernel:         status: c 
kernel: switching to power state:
kernel:         ui class: performance
kernel:         internal class: none
kernel:         caps: video 
kernel:         uvd    vclk: 0 dclk: 0
kernel:                 power level 0    sclk: 30000 mclk: 50000 vddc: 1200
kernel:                 power level 1    sclk: 72000 mclk: 50000 vddc: 1200
kernel:                 power level 2    sclk: 72000 mclk: 50000 vddc: 1200
kernel:         status: r

This is exactly what I'm referring to, I don't understand why would the card switch into a less power-efficient power state in this manner, since power level 2 in both states are identical and provide maximum performance.

Any insight would be greatly appreciated!

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