From: David Mosberger <davidm@napali.hpl.hp.com>
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 <davidm@hpl.hp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
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);
_