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Thread: No power management for HD3200?

  1. #1
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    Default No power management for HD3200?

    I just got a new laptop with HD3200 graphics, and it seems the power management is not woking for this video card. I've enabled these options:

    Option "ClockGating" "on"
    Option "ForceLowPowerMode" "on"
    Option "DynamicPM" "on"

    Using the radeon driver consumes about 10W more than using the fglrx driver! The difference between fglrx and radeon in power usage on my other laptop with HD3650 is just like 4-5W, so I assume that power management is not supported, or am I missing something?

    Any ideas?

    Thanks.

  2. #2
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    Default

    Can you pastebin your xorg log file, just in case there are any relevent error messages ?

    My guess is that you *are* getting power savings, just not as much (yet) as you would with a discrete GPU. The HD3200 is connected via HyperTransport rather than PCIE, and the drivers only have code for PCIE lane reduction, so I suspect they don't save as much power on an IGP as they do on a discrete GPU.

    The current power management code is just "the low hanging fruit" - it's maybe 1/10th as complex as the code in fglrx. Once kernel modesetting is in place I expect more sophisticated power management code will follow right behine.

    We also recently released programming docs for the 780 chipset, which will help withthe implementation of IGP-specific power management features.
    Last edited by bridgman; 08-27-2009 at 11:08 PM.

  3. #3
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    Besides PCI-E lanes reduction, isn't there also GPU clock reduction?

    Here's my xorg.conf:

    Code:
    Section "Monitor"
    	Identifier	"Configured Monitor"
    EndSection
    
    Section "Screen"
    	Identifier	"Default Screen"
    	Monitor		"Configured Monitor"
    	Device		"Configured Video Device"
    EndSection
    
    Section "Device"
    	Identifier	"Configured Video Device"
    	Driver "radeon"
    	Option "ClockGating" "on"
    	Option "ForceLowPowerMode" "on"
    	Option "DynamicPM" "on"
    EndSection
    
    Section "ServerFlags"
    	Option	"DontZap"	"False"
    EndSection

  4. #4
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    Default

    Can you pastebin your xorg log file please ?

  5. #5
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    Quote Originally Posted by bridgman View Post
    Can you pastebin your xorg log file please ?
    Here it is: http://pastebin.com/m56cab60d

  6. #6
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    Default

    That is not the log file :P

    /var/log/Xorg.0.log

  7. #7
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    Quote Originally Posted by RealNC View Post
    That is not the log file :P

    /var/log/Xorg.0.log
    Yes, sorry for that, I was half asleep when I posted. Here's the correct one:

    http://pastebin.com/m5ba68149

  8. #8
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    Thanks. Looks like the power saving options are running OK. The only interesting thing I saw was :

    (II) RADEON(0): ATOM BIOS Rom:
    SubsystemVendorID: 0x107b SubsystemID: 0x0700
    IOBaseAddress: 0x9000
    Filename: AJ6_V94.bin
    BIOS Bootup Message:
    GW_AjaxA78 RS780M DDR2 200e/500m

    <snip>

    (II) RADEON(0): Default Engine Clock: 500000
    (II) RADEON(0): Default Memory Clock: 400000
    The VBIOS description string talks about 200 MHz engine clock and 500 MHz memory clock, but subsequent messages mention a 500 MHz engine clock and 400 MHz memory clock. Not sure what to make of that yet.

    I imagine memory clock only matters if you have sideport memory on the HD3200, but we don't use sideport memory in the drivers yet AFAIK anyways.
    Last edited by bridgman; 08-31-2009 at 01:07 PM.

  9. #9
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    Well, that is strange... maybe the 200MHz is for "low power" mode and the 500MHz for the "performance" mode for the GPU?

    Anyways, I'm sure this computer does not have sideport memory. The computer is a Gateway MD6214u.
    Last edited by glock24; 08-31-2009 at 03:14 PM.

  10. #10
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    Memory clock isn't really relevant on IGP chips since it uses system memory which is controlled by the northbridge rather than the GPU.

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