Problems with snd_ich

[Damian Gerow]

I've got a K8WE, and up until a few days ago, snd_ich worked just fine under
6.0-BETA3:

    pcm0: <nVidia nForce4> port 0x1800-0x18ff,0x1400-0x14ff mem 0xc8002000-0xc8002fff irq 22 at device 4.0 on pci0
    pcm0: [GIANT-LOCKED]
    pcm0: <Analog Devices AD1981B AC97 Codec>

Then suddenly, anything playing sound started to hang, and no sound would
come out.  I don't remember doing anything at that point in time -- I came
back from work, and it just wasn't working.  This message appeared in dmesg:

    pcm0: ac97 link rate calibration timed out after 1795248 us

When it happened, I could unload snd_ich, but not sound.  And the problem's
been plaguing me ever since: as soon as I load the module, I get the link
rate calibration error.  I've since updated to BETA5, but am still seeing
the problem.  Additionally, when I tried to kldunload sound earlier today,
my kernel panicked:

    Fatal trap 12: page fault while in kernel mode
    fault virtual address   = 0xa0
    fault code              = supervisor read, page not present
    instruction pointer     = 0x8:0xffffffff8025155b
    stack pointer           = 0x10:0xffffffffa7bf79d0
    frame pointer           = 0x10:0x0
    code segment            = base 0x0, limit 0xfffff, type 0x1b
                            = DPL 0, pres 1, long 1, def32 0, gran 1
    processor eflags        = interrupt enabled, resume, IOPL = 0
    current process         = 53790 (kldunload)
    trap number             = 12
    panic: page fault
    Uptime: 9m45s

I didn't have a kernel with debugging symbols handy, unfortunately, but I've
got another one built and ready to go, and I'll see if I can reproduce the
panic later today.

  - Damian