Re: bug in Linux 2.4.19RC1 i815e agpgart module, unable to determineaperturesize.

[Nicolas Aspert]

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Knut J Bjuland wrote:
> Your patch fix my problem with the new i815 code. I run it through a quake3 test and it is as fast as the old
> code,
> Agpgart is now able to determine aperture size, I think you nailed  this problem. Thank you for your patch, hope
> it get in Linux 2.4.19.
> 

Ok that sounds like one bug killed ;-), so I guess this should go in for 
2.4.19-rc2 ...

Marcelo, please apply (patch is against 2.4.19-rc1). I know that Alan 
and Dave have also similar parts in their trees and they are likely to 
suffer the same problem.
Thanks Knut for pointing the problem (although it was present in 
2.4.19-pre10-ac2 already for sure...)

Best regards
Nicolas.
-- 
Nicolas Aspert      Signal Processing Institute (ITS)
Swiss Federal Institute of Technology (EPFL)

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diff -Nru linux-2.4.19-rc1.clean/drivers/char/agp/agpgart_be.c linux-2.4.19-rc1/drivers/char/agp/agpgart_be.c
--- linux-2.4.19-rc1.clean/drivers/char/agp/agpgart_be.c	Thu Jun 27 09:07:04 2002
+++ linux-2.4.19-rc1/drivers/char/agp/agpgart_be.c	Thu Jun 27 10:53:47 2002
@@ -1402,6 +1402,12 @@
 	aper_size_info_8 *values;
 
 	pci_read_config_byte(agp_bridge.dev, INTEL_APSIZE, &temp);
+
+        /* Intel 815 chipsets have a _weird_ APSIZE register with only
+         * one non-reserved bit, so mask the others out ... */
+        if (agp_bridge.type == INTEL_I815) 
+          temp &= (1 << 3);
+        
 	values = A_SIZE_8(agp_bridge.aperture_sizes);
 
 	for (i = 0; i < agp_bridge.num_aperture_sizes; i++) {

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