[issue1127] cdrom drive not detected
dillon at apollo.backplane.com
Thu Sep 17 08:38:01 PDT 2009
:I have a similar error on my home "debranded HP media PC" which is a
:Core2Duo intel chipset based motherboard, SATA hard disk and DVDRW, with
:bios option set to AHCI mode instead of IDE mode. With default boot
:options (no keyboard input) the CD fails to boot with same rootvp can't
:be found, apparently trying acd0, which doesn't exist under AHCI, and
:ends debugger prompt. If I watch the boot process and choose the "no
:AHCI" boot option, It finds the DVD rom and works fine, presumably
:because acd0 exists under nata. On a slightly older version, It would
:fail to the mountroot prompt and typing in cd9660:cd0 works sometimes or
:not with an "Device is in process of getting ready" type of message,
Hmm. A CD/DVD detected via the AHCI driver will probe as 'cd0'.
The root mount should try acd0, cd0, acd1, cd1, and cd8 (for USB
The AHCI driver is supposed to probe everything before mountroot
runs. If it isn't one way to test and debug the situation is
to type '?' + <return> at the mountroot> prompt several times.
If the CD/DVD is still being probed then it should show up in the
list after a few tries and you should then be able to specify it
as the root mount.
The question would then become: Why didn't it probe before the
mountroot? The AHCI driver explicitly probes devices before letting
CAM finish up and mountroot to proceed. To figure that out a verbose
boot is probably needed. Sometimes a verbose boot changes the timing
enough such that the problem might not show up at all though :-(.
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