I compared the output of the failing module load with dpm=1:

[    4.823925]     caps: 
[    4.823927]     uvd    vclk: 0 dclk: 0
[    4.823929]         power level 0    sclk: 15000 mclk: 15000 vddc: 950
vddci: 950 pcie gen: 3
[    4.823930]     status: c r b 
[    4.823934] == power state 1 ==
[    4.823935]     ui class: performance
[    4.823937]     internal class: none
[    4.823940]     caps: 
[    4.823941]     uvd    vclk: 0 dclk: 0
[    4.823943]         power level 0    sclk: 30000 mclk: 15000 vddc: 875
vddci: 850 pcie gen: 3
[    4.823945]         power level 1    sclk: 45000 mclk: 140000 vddc: 950
vddci: 1025 pcie gen: 3
[    4.823947]         power level 2    sclk: 103000 mclk: 140000 vddc: 1163
vddci: 1025 pcie gen: 3
[    4.823949]         power level 3    sclk: 108000 mclk: 140000 vddc: 1206
vddci: 1025 pcie gen: 3
[    4.823950]     status: 
[    4.823952] == power state 2 ==
[    4.823953]     ui class: none
[    4.823955]     internal class: uvd 
[    4.823957]     caps: video 
[    4.823959]     uvd    vclk: 72000 dclk: 56000
[    4.823960]         power level 0    sclk: 45000 mclk: 140000 vddc: 950
vddci: 1025 pcie gen: 3
[    4.823975]         power level 1    sclk: 45000 mclk: 140000 vddc: 950
vddci: 1025 pcie gen: 3
[    4.823977]         power level 2    sclk: 103000 mclk: 140000 vddc: 1163
vddci: 1025 pcie gen: 3
[    4.823979]     status: 
[    4.823980] == power state 3 ==
[    4.823981]     ui class: none
[    4.823982]     internal class: none
[    4.823984]     caps: 
[    4.823986]     uvd    vclk: 0 dclk: 0
[    4.823988]         power level 0    sclk: 30000 mclk: 15000 vddc: 875
vddci: 850 pcie gen: 3
[    4.823990]         power level 1    sclk: 30000 mclk: 15000 vddc: 875
vddci: 850 pcie gen: 3
[    4.823991]         power level 2    sclk: 30000 mclk: 15000 vddc: 875
vddci: 850 pcie gen: 3
[    4.823993]     status: 

With the VGA Bios someone uploaded here:

http://www.techpowerup.com/vgabios/150430/sapphire-r9270x-4096-131103.html

CCC Overdrive Limits
  GPU Clock: 1400.00 MHz
  Memory Clock: 1625.00 MHz
Clock State 0
  Core Clk: 1070.00 MHz
  Memory Clk: 1400.00 MHz
  Flags: Boot
Clock State 1
  Core Clk: 1070.00 MHz
  Memory Clk: 1400.00 MHz
  Flags: Optimal Perf
Clock State 2
  Core Clk: 1020.00 MHz
  Memory Clk: 1400.00 MHz
  Flags: UVD
Clock State 3
  Core Clk: 300.00 MHz
  Memory Clk: 150.00 MHz
  Flags: 

For power state 3 sclk and mclk corespond to Core Clk and Memory Clk.

In power state 2 sclk is 10 MHz lower, with power state 1 its 10 MHz higher
and in boot state its 100 MHz higher.

I don't know how the radeon DPM code figures the power state levels but
something is wrong here.

Can I force dpm into a power level at module load time? I suspect forcing into
state 3 should work.