Re: Panic during agp_intel attach

[christos%astron.com@localhost (Christos Zoulas)]

In article <18324.53999.69264.490129%guava.gson.org@localhost>,
Andreas Gustafsson <gson%gson.org@localhost> wrote:
>I tried booting -current (as of 20080118-1955 EET) on a Compaq DeskPro EN,
>but it paniced during boot.  Here's a partial backtrace:
>
>  #3  0xc05686dd in panic (fmt=0xc0c5ed04 "kernel %sassertion \"%s\"
>failed: file \"%s\", line %d") at ../../../../kern/subr_prf.c:204
>  #4  0xc098486f in __kernassert (t=0xc0beaa93 "diagnostic ",
>f=0xc0beaa6c "../../../../arch/x86/pci/pci_machdep.c", l=432,
>e=0xc0beaa5b "(reg & 0x3) == 0") at
>../../../../../../lib/libkern/__assert.c:50
>  #5  0xc07c2c88 in pci_conf_write (pc=0x0, tag={mode1 = 2147483648,
>mode2 = {port = 0, enable = 0 '\0', forward = 128 '\200'}}, reg=145,
>data=112) at ../../../../arch/x86/pci/pci_machdep.c:432
>  #6  0xc07c0932 in agp_intel_init (sc=0xc177e400) at
>../../../../dev/pci/agp_intel.c:266
>  #7  0xc07c05ea in agp_intel_attach (parent=0xc1785e00,
>self=0xc177e400, aux=0xc0e4978c) at ../../../../dev/pci/agp_intel.c:193
>  #8  0xc07bbd31 in agpattach (parent=0xc1785e00, self=0xc177e400,
>aux=0xc0e49788) at ../../../../dev/pci/agp.c:331
>
>Apparently this is triggered by the following change:
>
>  revision 1.31
>  date: 2008/01/14 18:44:17;  author: dyoung;  state: Exp;  lines: +4 -2
>  KASSERT() that reads/writes from/to PCI configuration space are
>  aligned on 32-bit boundaries.
>
>combined with the following code in agp_intel.c:
>
>                pci_conf_write(sc->as_pc, sc->as_tag,
>                        AGP_INTEL_ERRSTS, 0x70);
>
>and the following #define in agpreg.h:
>
>   #define AGP_INTEL_ERRSTS        0x91    /* Not i8XX */
>
>as 0x91 is not aligned to a 32-bit boundary.  What's the correct fix?

Try commenting out the pci_conf_write call.

christos