Le 05.03.2005 23:03, Alan Stern a écrit :
I'm never sure whether it's best to continue things like this on the mailing list so everyone can follow along or in the Bugzilla entry...
Don't know. IMHO, the bugzilla entry should be filled if a solution is found (or not found :-( ). It's up to you, USB guys.
[snip]
What's happening is that the system is failing to initialize the mouse correctly. There are multiple retries (and multiple _layers_ of retries!) and the timeout is set to 5 seconds. Hence the delays apparent in your syslog. During that time the /proc/bus/usb/devices file is basically locked, so the process attempting to read it gets blocked.
I assume nothing like this happens during a normal bootup, only when you use kexec? Actually I'm not at all familiar with how kexec works; can someone provide a quick explanation?
Yes, it occurs *only after kexec*, never after a cold boot or after a normal reboot (ie reboot without kexec).
If you rmmod uhci-hcd before the kexec and then modprobe it afterward, do detection and initialization of the mouse work okay?
Yes, if I rmmod uhci-hcd before the kexec, detection and initialization works okay.
Assuming yes, it appears that uhci-hcd isn't reacting well to kexec. How does kexec impinge on the driver, and what is it supposed to do?
Alan Stern
P.S.: For a possibly related bug report, see
http://bugme.osdl.org/show_bug.cgi?id=4276
On my box, I have a PS/2 mouse, an USB webcam and an USB joystick. They are _always_ plugged in. The problem occurs only after kexec. There is no problem where I do a cold boot.
In bug report 4276, the problem appears when the USB mouse is plugged and disappears when USB mouse is unplugged on boot.
So it seems to me they are different problems.
Le 05.03.2005 23:31, Alan Stern a écrit : [snip]
I just noticed the "irq 5 - nobody cared" line in your dmesg log. You probably need to specify the "usb-handoff" boot parameter in your kexec command line. Most likely that will fix everything.
Yes, it does help.
If it doesn't help, can you mount a debugfs filesystem and post the contents of .../uhci/0000:00:04.2 and .../uhci/0000:00:04.3 from both the pre-kexec kernel and the post-kexec kernel? You'll have to set CONFIG_USB_DEBUG first.
Alan Stern
-- laurent
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