Re: [Qemu-devel] [PATCH] [RFC] Variable video ram size option

[Trolle Selander <trolle.selander@eu.citrix.com>]

Paul Brook wrote:
>> While I have my doubts about there being any applications or games using
>> VBE & triple buffering that will actually run at 2560x1600 with any kind
>> of decent performance , I also see no reason to set this limit any lower
>> than the theoretically usable max, so 48 Megs it is.
>>     
>
> You're missing the point. There is no "usable max". The only limits are those 
> implied by 16-bit coordinates, address space, and the imagination of the 
> programmer.
>
> Paul
>
>   
True, but my thought was mainly that most of these "vram tricks" are 
very unlikely to be used by any software run in the VM and thus ending 
up going to waste and moreover  (probably) pointless in a virtual 
architecture where there is no slow bus between videocard ram and system 
ram.
In any case, the discussion here has made me reconsider whether we 
should not enforce any "artificial" limit, and just put recommendations 
for "sane" in the manpage, since ultimately, my reason for putting the 
limit in was mostly to prevent users from naively allocationg 
"pointless" amounts of vram that will almost certainly be wasted. The 
amounts of "graphic card ram" common today might easily cause new users 
to make this mistake. What's everyone else's thoughts on this? I'm 
preparing a slightly updated version of the patch, and I'd like to hear 
whether everyone agrees there should be no artificial limit enforced.

Just out of curiosity, does anyone have any example of an existing 
application using VBE that makes use of more than triple-buffered (xres 
* yres * 4) RAM?

-- Trolle