ati graphics on laptops

[Joel Jaeggli]

On Tue, 11 Oct 2005, David Becker wrote:

> Steffen Kluge wrote:
>> On Tue, 2005-10-11 at 09:32 +0200, David Becker wrote:
>>> Sorry if I sound like I'm whining over this, but the market has become
>>> so untransparent because of these architectures.
>>
>> No worries, this is very interesting.
>>
>> Btw, "lcpci -v" reports 128MB of memory for the X300, I assume 64MB
>> on-board + 64MB extra?
>>
>> Strangely, the "stolen" 64MB aren't missing in the output of "free" (as
>> is the case with shared video memory adapters).
>
> It could be that 128MB reflects the graphics card's addressable memory
> while the extra 64MB is not actually in use.
> You'd have to run something that uses more than 64MB VRAM and then check
> the available system memory. It's not unlikely that the hypermemory is
> reflected differently than shared memory.

radeon x300 mobile parts are available in 3 flavors...

32mb, 64mb, discrete... while the discrete part could potetially have no 
memory attached, it would be more common for it to have some attached. 
dell for example  sells the inspiron 6000 with x300's that have either 
no memory (64MB hypermemory they call it) or 128MB. desktop x300's with 
256MB of ram do exist, though why you would get one is another question 
entirely.

> Hypotheses:
> Graphics card has 64MB on board memory
> Graphics card can address 128MB VRAM
> Hypermemory architecture allocates system memory for vram on demand
> Shared memory architectures allocates system memory for vram on power up
>
> So given these hypotheses, a plain-vanilla shared memory architecture
> immediately reserves system memory vram, while the hypermemory (shared
> memory) architecture only uses/reserves the augmented memory when it's
> out of on board vram?
>
> It get's more confusing since a cousin of mine recently purchased a
> laptop based on ATI's 200M chipset. I haven't run linux on it, but
> Windows reports 512MB-128MB system memory. And the graphics card uses
> 128MB shared memory. Given that this card follows the hypermemory
> architecture and my hypothesis on how hypermemory is allocated/reserved,
> windows should report the system memory as more than 512-128. Either
> Windows reports this differently than linux, or the ATI 200M chipset
> immediately (on power up) reserves system memory for VRAM because this
> particular card doesn't have *any* on board memory. Or my hypothesis on
> the difference in behaviour between HyperMemory and Shared Memory
> architectures with respect to system memory reservation is wrong.
>
> If these laptops were mine, I'd open them up and look at the graphics card.
>
> Things are getting hairy.
>
> regards,
>
> 	David
>
>

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Joel Jaeggli  	       Unix Consulting 	       joelja at darkwing.uoregon.edu
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