X start failure

Current system from December 25.  When booting directly into
multi-user state, X starts but xdm fails to start the user session
with a message about "(EE) GARTInit: Unable to open /dev/agpgart (No
such file or directory)"  However xdm starts the user session just
fine when X is started after exiting from single user mode.  I still
have the GART error message in xdm.log, but the user session works
fine.  I believe this behavior is new in the last week.

pciconf -lv reveals:
hostb0_at_pci0:0:0:        class=0x060000 card=0x054a1014 chip=0x35808086 rev=0x01
 hdr=0x00
    vendor   = 'Intel Corporation'
    device   = '82852GM/GME/GMV/PM, 855GM/GME Montara Host-Hub Interface Bridge
'
    class    = bridge
    subclass = HOST-PCI
none0_at_pci0:0:1: class=0x088000 card=0x054b1014 chip=0x35848086 rev=0x01 hdr=0x0
0
    vendor   = 'Intel Corporation'
    device   = '82852GM/GME/GMV/PM, 855GM/GME Montara System Memory Controller'
    class    = base peripheral
none1_at_pci0:0:3: class=0x088000 card=0x054c1014 chip=0x35858086 rev=0x01 hdr=0x0
0
    vendor   = 'Intel Corporation'
    device   = '82852GM/GME/GMV/PM, 855GM/GME Montara Configuration Process'
    class    = base peripheral
vgapci0_at_pci0:2:0:       class=0x030000 card=0x05431014 chip=0x35828086 rev=0x01
 hdr=0x00
    vendor   = 'Intel Corporation'
    device   = '82852GM/GME/GMV/PM, 855GM/GME Montara Integrated Graphics Devic
e'
    class    = display
    subclass = VGA
vgapci1_at_pci0:2:1:       class=0x038000 card=0x05431014 chip=0x35828086 rev=0x01
 hdr=0x00
    vendor   = 'Intel Corporation'
    device   = '82852GM/GME/GMV/PM, 855GM/GME Montara Integrated Graphics Devic
e'
    class    = display
It seems that there have been some recent changes to agp_intel.c that
may have an impact on this, but I don't understand enough of what's
been done to attempt undoing it.

Can anybody tell me what's going on here?

-- 
Derek Tattersall   | All the passions make us commit faults; love makes
                   | us commit the most ridiculous ones.   -- La
dlt_at_mebtel.net     | Rochefoucauld 
dtatters_at_gmail.com | 
dlt666_at_yahoo.com   |