kern/109724: X11 fonts corrupt when loading i915 at boot time

[FUJIMOTO Kou]

>Number:         109724
>Category:       kern
>Synopsis:       X11 fonts corrupt when loading i915 at boot time
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Mar 01 16:20:05 GMT 2007
>Closed-Date:
>Last-Modified:
>Originator:     FUJIMOTO Kou
>Release:        6.2-STABLE
>Organization:
Tokyo Denki University
>Environment:
FreeBSD fosters 6.2-STABLE FreeBSD 6.2-STABLE #31: Fri Mar  2 00:05:12 JST 2007     root at fosters:/usr/obj/usr/src/sys/FOSTERS  i386

>Description:
When I load i915.ko at /boot/loader.conf (or enabled in kernel), kernel recognize my 855GME internal VGA controller as: 
=====================================================================
agp1: <Intel 82855GME (855GME GMCH) SVGA controller> port 0xe300-0xe307 mem 0xe0000000-0xe7ffffff,0xe8100000-0xe817ffff irq 16 at device 2.0 on pci0
agp1: detected 32636k stolen memory
agp1: aperture size is 128M
drmsub0: <Intel i852GM/i855GM GMCH>: (child of agp_i810.c) on agp1
info: [drm] AGP at 0xd0000000 256MB
info: [drm] Initialized i915 1.5.0 20060119
=====================================================================
After finishing boot sequence, X works but fonts looks like corrupted. 
Kernel reports "agp_generic_alloc_memory: unsupported type 2" 
messages 3 times.

Just unloading all related KLMs (i915, drm and agp) and reloading them, 
kernel messages are as follows:
=====================================================================
drmsub0: detached
agp1: detached
agp_intel_detach: set MCHCFG to 1
agp_intel_detach: set NBXCFG to 540101
agp0: detached
agp0: <Intel 82855GME (855GME GMCH) SVGA controller> port 0xe300-0xe307 mem 0xe0000000-0xe7ffffff,0xe8100000-0xe817ffff irq 16 at device 2.0 on pci0
agp0: detected 32636k stolen memory
agp0: aperture size is 128M
drmsub0: <Intel i852GM/i855GM GMCH>: (child of agp_i810.c) on agp0
info: [drm] AGP at 0xe0000000 128MB
info: [drm] Initialized i915 1.5.0 20060119
=====================================================================
X works fine and all fonts are displayed without any corruption.

>How-To-Repeat:
i915_enable="YES" in /boot/loader.conf, or build agp, drm and i915drm 
devices into kernel.

>Fix:
1. Configuring kernel without agp, drm and i915drm.
2. Boot without loading i915.
3. "kldload i915" at command prompt.

>Release-Note:
>Audit-Trail:
>Unformatted: