FreeBSD kernel doesn't boot on FUJITSU PRIMERGY RX200 S5 server
Maxim Sobolev
sobomax at FreeBSD.org
Tue Apr 27 20:26:05 UTC 2010
John Baldwin wrote:
> Hmm, I think you should definitely commit the atkbdc_isa.c change first of
> all. I'm still thinking about the other change. I wonder if we can figure
> out that a keyboard isn't present sooner somehow? Do you know if the keyboard
> appears to be present but just slow vs if the keyboard is eventually found to
> not be present?
Our syscons does keyboard probing two times - once early during kernel
initialization before most of the subsystems have been initialized yet,
and then "real" probing later in boot process. Interesting thing is that
initially keyboard looks present. Reading status port in
atkbdc_configure() gives value other than 0xff, although reading is
thousand times slower than usually. This causes syscons try attaching
it. Even though reading status port works, apparently either emulation
is not complete or there is some other issue, so that it never responds
to some commands. Slow access and lack of response results in
wait_for_data() function waiting several minutes instead of 200ms as
designed. This what causes that 6-10 minutes delay in boot process.
In fact I've also tried sending 0xAA command instead of just checking
that value read from the status port is not 0xFF, and it actually
completed fine at this point. The controller has returned 0x55 as
expected. Therefore, I believe measuring inb() delay is the only
reasonable way to avoid that big boot delay at this point.
Later on, when we probe/attach keyboard second time (in atkbdc_isa.c)
reading status port returns 0xff, so the we can fail attachment process
immediately. However, this is not a big issue since at this point
reading from status port is as fast as any other ISA inb() operations,
so it doesn't cause any noticeable delay.
Here is the latest version of the patch:
http://sobomax.sippysoft.com/atkbdc.diff
-Maxim
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