2006-08-23 09:14:35

by Gerhard Pircher

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Subject: Question about aper_size_info structs in agp.h

Hi,

I was wondering about the differences between the aperture size types defined in agp.h. As far as I understand the size_value field in the aper_size_info_8/16/32 structs just defines the value to be set in the AGP bridge registers to configure a specific AGP aperture size (e.g. 8 MB, 16MB, etc..).

Wouldn't it be sufficient to define size_value as 32 bit only, or does the type of size_value/aper_size_info_x have an influence on the generation of the graphics address remapping table (e.g. address alignment) ?

For example the uninorth driver uses the aper_size_info_32 struct to define the AGP aperture size, but only defines values between 1 and 64 for the size_value field (so aper_size_info_8 would be sufficient).

BTW: Can anybody explain the format of the graphics address remapping table or point me to some docs where it is described?

regards,

Gerhard

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