[AGPGART] Disable calibration cycle when not in AGP3 mode of operation on AGP3 chipset.

drivers/char/agp/agp.h

@@ -395,6 +395,7 @@ unsigned long agp_generic_mask_memory(unsigned long addr, int type);
 #define AGPSTAT			0x4
 #define AGPCMD			0x8
 #define AGPNISTAT		0xc
+#define AGPCTRL                 0x10
 #define AGPNEPG			0x16
 #define AGPNICMD		0x20
 

drivers/char/agp/generic.c

@@ -545,7 +545,7 @@ EXPORT_SYMBOL(get_agp_version);
 
 void agp_generic_enable(u32 mode)
 {
-	u32 command;
+	u32 command, temp;
 	u32 agp3;
 
 	get_agp_version(agp_bridge);
@@ -577,6 +577,12 @@ void agp_generic_enable(u32 mode)
 			agp_device_command(command, TRUE);
 			return;
 		} else {
+		    /* Disable calibration cycle in RX91<1> when not in AGP3.0 mode of operation.*/            
+		    command &= ~(7<<10) ;
+		    pci_read_config_dword(agp_bridge->dev, agp_bridge->capndx+AGPCTRL, &temp);
+		    temp |= (1<<9);
+		    pci_write_config_dword(agp_bridge->dev, agp_bridge->capndx+AGPCTRL, temp);
+		    
 		    printk (KERN_INFO PFX "Device is in legacy mode,"
 				" falling back to 2.x\n");
 		}