Re: AGP aperture size detection 32b vs. 64b kernels

From: Ingo Molnar
Date: Mon Feb 23 2009 - 03:47:28 EST



* Yinghai Lu <yinghai@xxxxxxxxxx> wrote:

> drivers/char/agp/amd64-agp.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> Index: linux-2.6/drivers/char/agp/amd64-agp.c
> ===================================================================
> --- linux-2.6.orig/drivers/char/agp/amd64-agp.c
> +++ linux-2.6/drivers/char/agp/amd64-agp.c
> @@ -271,15 +271,15 @@ static __devinit int fix_northbridge(str
> nb_order = (nb_order >> 1) & 7;
> pci_read_config_dword(nb, AMD64_GARTAPERTUREBASE, &nb_base);
> nb_aper = nb_base << 25;
> - if (agp_aperture_valid(nb_aper, (32*1024*1024)<<nb_order)) {
> - return 0;
> - }
>
> /* Northbridge seems to contain crap. Try the AGP bridge. */
>
> pci_read_config_word(agp, cap+0x14, &apsize);
> - if (apsize == 0xffff)
> + if (apsize == 0xffff) {
> + if (agp_aperture_valid(nb_aper, (32*1024*1024)<<nb_order))
> + return 0;
> return -1;
> + }
>
> apsize &= 0xfff;
> /* Some BIOS use weird encodings not in the AGPv3 table. */
> @@ -301,6 +301,11 @@ static __devinit int fix_northbridge(str
> order = nb_order;
> }
>
> + if (nb_order >= order) {
> + if (agp_aperture_valid(nb_aper, (32*1024*1024)<<nb_order))
> + return 0;
> + }
> +

if the fix does the trick then please do some cleanups as well:
for example the 32MB magic constant should go into a define.

Ingo
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