Red Hat Bugzilla – Bug 175670
usb storage device present at boot fails to produce /dev/sd* (sda) device link
Last modified: 2007-11-30 17:11:19 EST
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Description of problem:
[root@anon ~]# cat /proc/scsi/scsi
Host: scsi0 Channel: 00 Id: 00 Lun: 00
Vendor: TOSHIBA Model: MK1032GAX Rev: AB21
Type: Direct-Access ANSI SCSI revision: 02
The device is present and known to the scsi subsystem. No other external storage devices are present.
There are no /dev/sd* enteries.
If the device is plugged in after boot everything works fine with scsi0 mapping to /dev/sda. If the
device is subsequently unplugged and replugged both devices will increment.
scsi0 -> /dev/sda
scsi1 -> /dev/sdb
scsi2 -> /dev/sdc
An odd twist is if in the broken case of device present at boot a unplug/plug event will produce
scsi1 -> /dev/sda
scsi2 -> /dev/sdb
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. plug in usb external hard drive enclosure to powered down machine
2. boot the machine
3. review /proc/scsi/scsi and verify device /dev/sd* not present
Actual Results: device is not present
Expected Results: device should be present at /dev/sda (or /dev/sd* something)
I tested this enclosure on FC2 and the behavior is different. /dev/sda is always reliably present (even from
boot) though the scsi device number will increment on unplug/plug events.
scsi0 -> /dev/sda
scsi1 -> /dev/sda
scsi2 -> /dev/sda
Running from /dev ./MAKEDEV sda seems to function as a workaround [I'll try
restricting the number of devices created later :) ]
FC4 is an udev-based system, so device nodes are created when a device is
attached. I suppose something races and udev does not realize that a device
is present when the system is booting.
Please attach the /var/log/messages (but DO NOT DROP IT INTO COMMENTS BOX,
and do not edit it).
I think I've seen this before. We're not sending hotplug events to udev if we
boot up with the device already connected iirc.
Created attachment 122202 [details]
/var/log/messages per request
The messages looks as if start_udev and the startup SCSI replay may not
be involved. I'm adding Harald to cc:, maybe he has ideas.
scsi hotplay replay is emulated by looking in /sys/devices for host* and there
for "type". For these devices a hotplug event is emulated.
I'm seeing this too, one on a Dell Notebook (D600, USB2 Intel Chipset) and
another on an old Dell Server (Dual Processor, USB1, Serverworks chipset I
think) with both a USB key and an ipod. Can give me details if req.
This is a mass-update to all currently open kernel bugs.
A new kernel update has been released (Version: 2.6.15-1.1830_FC4)
based upon a new upstream kernel release.
Please retest against this new kernel, as a large number of patches
go into each upstream release, possibly including changes that
may address this problem.
This bug has been placed in NEEDINFO_REPORTER state.
Due to the large volume of inactive bugs in bugzilla, if this bug is
still in this state in two weeks time, it will be closed.
Should this bug still be relevant after this period, the reporter
can reopen the bug at any time. Any other users on the Cc: list
of this bug can request that the bug be reopened by adding a
comment to the bug.
If this bug is a problem preventing you from installing the
release this version is filed against, please see bug 169613.
Due to a conflict with udev (upgrade required by new kernel) and syncing with an external LCD monitor I
am unable to test this out effectively.
<a href="https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=179951">udev bug</a>
With the udev situation resolved, the new kernel did not produce any change for this bug.
[This comment added as part of a mass-update to all open FC4 kernel bugs]
FC4 has now transitioned to the Fedora legacy project, which will continue to
release security related updates for the kernel. As this bug is not security
related, it is unlikely to be fixed in an update for FC4, and has been migrated
Please retest with Fedora Core 5.
/dev/sd* entries are present at boot with FC5 so this bug is closed I suppose, but there are issues with
mount points being assigned in FC5 . . . separate issue though.