Announcing Q3C09 for XO-1.5
quozl at laptop.org
Fri Aug 31 18:14:45 EDT 2012
On Fri, Aug 31, 2012 at 03:16:43PM -0500, Mikus Grinbergs wrote:
> Edit after having written up the text below the ---- divider:
> Have swapped XO-1.5s, adapters, hubs. The "no root device" kernel
> panic shows up with q3c09 wherever a particular Belkin F5U 234 (Rev
> 3) external USB hub is plugged in. [With other hubs, of the same or
> different models, the problem does not show up.]
I'll speculate that the kernel panic is due to the initial ramdisk not
being loaded by the firmware before the kernel is handed control. And
that suggests the problem might be in Open Firmware's handling of the
particular USB hub you have.
To eliminate that possibility, please get to the ok prompt, type p2
and describe for me the output, then type boot and press enter. Watch
carefully to make sure it says "Loading ramdisk image from". Tell me
if you see that.
> On 08/31/2012 09:09 AM, Samuel Greenfeld wrote:
> >Open Firmware knows how to use certain types of USB Ethernet adapters in
> >addition to the internal Wifi adapter, and supports accessing files via
> >many network protocols in addition to local means. You can tell OFW to
> >(with the slashes intentionally backwards) and it would try to get on a
> >network and install the build that way.
> >Does your network provide network-based boot services ?
> In this instance I was merely attempting to __boot__ the XO-1.5, and
> had not specified any URLs to the firmware (had not stopped at the
> ok prompt; had not typed in anything).
> My assumption is that if I do not explicitly tell the firmware to
> access an external resource, it will __not__ go looking for one.
> Is my assumption wrong?
Yes, but only slightly, and in your situation there should be no radio
Open Firmware has a boot device list. The manufacturing tag BD can be
used to constrain it. By default on XO-1.5 the list contains, in
" u:\boot\olpc.fth ext:\boot\olpc.fth int:\boot\olpc.fth /prober /usb/ethernet /wlan"
So if you have no USB storage with a /boot/olpc.fth file, and you have
no external SD card or internal microSD card file of the same name,
and you have no USB ethernet device (compatible with Open Firmware and
not hidden behind a hub that is incompatible), then the wireless LAN
will be used, with a default network name of OLPCOFW. It won't use
any other network, by default. The OLPCOFW network must provide DHCP
and a boot service.
In your situation, since you have installed os21, the second or third
items in the list should prevent further searching.
> Yes, I do have a wireless AP active, which would perform DHCP
> assignment if contacted. I was relying upon information from the
> __build__ (once the XO got initialized) -- 'ifconfig' does not show
> any wireless connection. Are you saying that when I power up, OFW
> will search for radio signals even when I have not told it to do so
ifconfig won't show what Open Firmware might have done, because the
kernel reinitialises the wireless card rather than obtain information
from it on how it is configured.
> The XO is using whatever /bootpart contents os21 installs -
> including that build's original
> '/bootpart/boot-versions/21/olpc.fth' file. My assumption is that
> OFW isn't attempting any "fully network boot".
> [Besides - how would OFW know the passphrase for the wireless network ?]
> p.s. By the way, my XO-1.5 configuration is :
> External SD card plugged in at bottom of XO
> Contains one data partition (ext2) and one swap partition
> USB hub plugged in at left side of XO
> Keyboard plugged in to USB hub
> Mouse plugged in to USB hub
> USB ethernet adapter plugged in at right side of XO
Thanks. In further replies I'll assume this remains the same.
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