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

[Nicolas Aspert <Nicolas.Aspert@epfl.ch>]

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Adrian Bunk wrote:

> Since -rc1 agpgart_be.c uses for the 815 new 815-specific instead of the
> generic intel functions.
> 
> Could you try whether reverting the following part of the patch fixes the
> problem?
> 
> --- linux/drivers/char/agp/agpgart_be.c	2002-06-04 01:22:07.000000000 +0000
> +++ linux/drivers/char/agp/agpgart_be.c	2002-06-24 15:23:36.000000000 +0000
> @@ -3929,7 +4005,7 @@
>  		INTEL_I815,
>  		"Intel",
>  		"i815",
> -		intel_generic_setup },
> +		intel_815_setup },
>  	{ PCI_DEVICE_ID_INTEL_820_0,
>  		PCI_VENDOR_ID_INTEL,
>  		INTEL_I820,
> 
> 
> 

Hello

I suspect that the problem (from what you sent) comes from the 
'intel_8xx_fetch_size' function. The APSIZE register has only one bit 
with valuable information with intel815 chipset, all other bits are 
'reserved'. The problem you saw may come from reading those reserved bits.
I attach a patch against 2.4.19-rc1 that aims at fixing this. Could you 
please test and report whether things get better/worse ?

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 08:56:02 2002
+++ linux-2.4.19-rc1/drivers/char/agp/agpgart_be.c	Thu Jun 27 08:59:21 2002
@@ -1402,6 +1402,10 @@
 	aper_size_info_8 *values;
 
 	pci_read_config_byte(agp_bridge.dev, INTEL_APSIZE, &temp);
+
+        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++) {