Understanding kdrive ati driver UploadToScreen function.

[Abhinav Duggal]

Hi all,
I was going through ati kdrive driver.The UploadToScreen gets a src pointer
to the memory region to copy to the destination.But this address is a
virtual space address.This address is used as follows to perform the upload
operation.
ATIUploadToScreen(PixmapPtr pDst, char *src, int src_pitch)
{
.....
.....
//code from  hw/kdrive/ati_draw.c
BEGIN_DMA(1);
  OUT_RING(((CARD32 *)src)[i]);
  END_DMA();
....
....
}
How does sga accelerator use this address for copying.To my knowledge
graphics accelerator does not have any knowledge of the this virtual
address.The ati graphics  accelerator needs a physical address to perform
the copy.How is this done?Correct me if i am wrong anywhere.I am not very
clear about what is this DMA being used for.
Actually, I have a similar situation.I am writing a kdrive driver for my
graphics card.And i need a physical address corresponding to this virtual
address which i will feed to my graphics accelerator.Please help.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.x.org/archives/xorg/attachments/20070503/cf154085/attachment.html>