Bug 33875 – Missing entries in agp_bridge_info structure setup in 2.4.22_ac4 kernel

• Status: RESOLVED UPSTREAM
• Product: Gentoo Linux

[Description spambox 2003-11-19 16:39:58 UTC]

When using the 2.4.22-ac4 kernel, which (in theory) supports the nVidia nForce
AGP GART on a nVidia nForce 2 motherboard, the following error pops up in dmesg
when trying to load agpgart.o:
Linux agpgart interface v0.99 (c) Jeff Hartmann
agpgart: Maximum main memory to use for agp memory: 439M
agpgart: unsupported bridge
agpgart: no supported devices found

I did some poking around and found that in 2.4.22-ac4, there's no entry for
CONFIG_AGP_NVIDIA in the structure initialization of agp_bridge_info in
/usr/src/linux/drivers/char/agp/agpgart_be.c

Further investigation shows this code was in 2.4.22-ac2. The missing stuff seems
to be:

#ifdef CONFIG_AGP_NVIDIA
        { PCI_DEVICE_ID_NVIDIA_NFORCE,
                PCI_VENDOR_ID_NVIDIA,
                NVIDIA_NFORCE,
                "NVIDIA",
                "nForce",
                nvidia_generic_setup },
        { PCI_DEVICE_ID_NVIDIA_NFORCE2,
                PCI_VENDOR_ID_NVIDIA,
                NVIDIA_NFORCE2,
                "NVIDIA",
                "nForce2",
                nvidia_generic_setup },
        { 0,
                PCI_VENDOR_ID_NVIDIA,
                NVIDIA_GENERIC,
                "NVIDIA",
                "Generic",
                nvidia_generic_setup },
#endif /* CONFIG_AGP_NVIDIA */

It should be somewhere in the set of #ifdefs for different hardware support--
forgive me for not generating a diff; truth told I'm not quite sure how. 




Reproducible: Always
Steps to Reproduce:
1. Have a nVidia nForce2 motherboard. I don't think it matters, but I have an
Asus A7N8X Deluxe with an ATI Radeon 9000 plugged into the AGP socket
2.Compile up a 2.4.22-ac4 kernel. Be sure to enable agpgart support, and support
for nForce motherboards
3.modprobe agpgart.  Feel free to set agp_try_unsupported; it doesn't help.

Actual Results:  
/lib/modules/2.4.22-ac4/kernel/drivers/char/agp/agpgart.o: init_module: No such
Hint: insmod errors can be caused by incorrect module parameters, including
invar IRQ parameters.
      You may find more information in syslog or the output from dmesg
/lib/modules/2.4.22-ac4/kernel/drivers/char/agp/agpgart.o: insmod
/lib/modules/24/kernel/drivers/char/agp/agpgart.o failed
/lib/modules/2.4.22-ac4/kernel/drivers/char/agp/agpgart.o: insmod agpgart failed

Checking dmesg shows:

Linux agpgart interface v0.99 (c) Jeff Hartmann
agpgart: Maximum main memory to use for agp memory: 439M
agpgart: unsupported bridge
agpgart: no supported devices found.



Expected Results:  
Load the AGP GART module. :) Modprobe should return with no errors, dmesg should
then say:

Linux agpgart interface v0.99 (c) Jeff Hartmann
agpgart: Maximum main memory to use for agp memory: 439M
agpgart: Detected NVIDIA nForce2 chipset
agpgart: AGP aperture is 256M @ 0xc0000000

Portage 2.0.49-r15 (default-x86-1.4, gcc-3.2.3, glibc-2.3.2-r3, 2.4.22-ac4)
=================================================================
System uname: 2.4.22-ac4 i686 AMD Athlon(tm) XP 1700+
Gentoo Base System version 1.4.3.10
ACCEPT_KEYWORDS="x86"
AUTOCLEAN="yes"
CFLAGS="-O3 -march=athlon-xp -funroll-loops -pipe"
CHOST="i686-pc-linux-gnu"
COMPILER="gcc3"
CONFIG_PROTECT="/etc /var/qmail/control /usr/share/config
/usr/kde/2/share/config /usr/kde/3/share/config"
CONFIG_PROTECT_MASK="/etc/gconf /etc/env.d"
CXXFLAGS="-O3 -march=athlon-xp -funroll-loops -pipe"
DISTDIR="/usr/portage/distfiles"
FEATURES="sandbox ccache autoaddcvs"
GENTOO_MIRRORS="http://212.219.247.14/sites/www.ibiblio.org/gentoo/
http://mirror.clarkson.edu/pub/distributions/gentoo/
ftp://ftp.ussg.iu.edu/pub/linux/gentoo
http://www.gtlib.cc.gatech.edu/pub/gentoo"
MAKEOPTS="-j2"
PKGDIR="/usr/portage/packages"
PORTAGE_TMPDIR="/var/tmp"
PORTDIR="/usr/portage"
PORTDIR_OVERLAY=""
SYNC="rsync://rsync.gentoo.org/gentoo-portage"
USE="x86 oss apm arts avi crypt cups encode foomaticdb gif gtk imlib jpeg kde
libg++ libwww mad mikmod motif mpeg ncurses nls oggvorbis opengl pdflib png qt
quicktime sdl spell svga truetype xml2 xmms xv zlib gdbm berkdb slang readline gpm
tcpd pam ssl perl python X gtk2 gnome alsa video_cards_radeon"

[Comment 1 spambox 2003-11-19 16:42:56 UTC]

Adding the lines mentioned above to agpgart_be.c sure enough yields me an agpgart.o that seems to load successfully, though I've not dug far enough to find if I broke anything else in the process.

[Comment 2 Brian Jackson (RETIRED) 2003-11-19 20:00:48 UTC]

We don't prepare the -ac patch, you should report this error to Alan Cox, bugzilla.kernel.org, or LKML. However, I wouldn't hold my breath, Alan Cox has gone on a year long hiatus.