From: David Mosberger As mentioned earlier, the current check_bridge_mode() code assumes that AGP bridges are PCI devices. This isn't always true. Definitely not for HP zx1 chipset and the same seems to be the case for SGI's AGP bridge. The patch below fixes the problem by picking up the AGP_MODE_3_0 bit from bridge->mode. I feel like I may be missing something, since I can't see any reason why check_bridge_mode() wasn't doing that in the first place. According to the AGP 3.0 specs, the AGP_MODE_3_0 bit is determined during the hardware reset and cannot be changed, so it seems to me it should be safe to pick it up from bridge->mode. With the patch applied, I can definitely use AGP acceleration both with AGP 2.0 and AGP 3.0 (one with an Nvidia card, the other with an ATI FireGL card). Signed-off-by: David Mosberger-Tang Signed-off-by: Andrew Morton --- 25-akpm/drivers/char/agp/generic.c | 19 +++---------------- 1 files changed, 3 insertions(+), 16 deletions(-) diff -puN drivers/char/agp/generic.c~fix-agp-code-to-work-again-with-non-pci-agp-bridges drivers/char/agp/generic.c --- 25/drivers/char/agp/generic.c~fix-agp-code-to-work-again-with-non-pci-agp-bridges 2005-04-04 17:50:50.000000000 -0700 +++ 25-akpm/drivers/char/agp/generic.c 2005-04-04 17:50:50.000000000 -0700 @@ -295,19 +295,6 @@ int agp_num_entries(void) EXPORT_SYMBOL_GPL(agp_num_entries); -static int check_bridge_mode(struct pci_dev *dev) -{ - u32 agp3; - u8 cap_ptr; - - cap_ptr = pci_find_capability(dev, PCI_CAP_ID_AGP); - pci_read_config_dword(dev, cap_ptr+AGPSTAT, &agp3); - if (agp3 & AGPSTAT_MODE_3_0) - return 1; - return 0; -} - - /** * agp_copy_info - copy bridge state information * @@ -328,7 +315,7 @@ int agp_copy_info(struct agp_bridge_data info->version.minor = bridge->version->minor; info->chipset = SUPPORTED; info->device = bridge->dev; - if (check_bridge_mode(bridge->dev)) + if (bridge->mode & AGPSTAT_MODE_3_0) info->mode = bridge->mode & ~AGP3_RESERVED_MASK; else info->mode = bridge->mode & ~AGP2_RESERVED_MASK; @@ -661,7 +648,7 @@ u32 agp_collect_device_status(struct agp bridge_agpstat &= ~AGPSTAT_FW; /* Check to see if we are operating in 3.0 mode */ - if (check_bridge_mode(agp_bridge->dev)) + if (agp_bridge->mode & AGPSTAT_MODE_3_0) agp_v3_parse_one(&requested_mode, &bridge_agpstat, &vga_agpstat); else agp_v2_parse_one(&requested_mode, &bridge_agpstat, &vga_agpstat); @@ -732,7 +719,7 @@ void agp_generic_enable(struct agp_bridg /* Do AGP version specific frobbing. */ if (bridge->major_version >= 3) { - if (check_bridge_mode(bridge->dev)) { + if (bridge->mode & AGPSTAT_MODE_3_0) { /* If we have 3.5, we can do the isoch stuff. */ if (bridge->minor_version >= 5) agp_3_5_enable(bridge); _