Hide Forgot
From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4.3) Gecko/20040924 Description of problem: Dual Xeon Dell Precision 650n (3.06 GHz; CPU family 15) freezes or restarts during kernel startup when booting the SMP kernel if "USB Emulation" and "USB Controller" are enabled in the BIOS. The same behavior exists in kernels back at least to kernel-smp-2.4.21-15.0.2.EL. The system boots normally with single-processor RHEL kernels. When USB is disabled in the system BIOS, both single- and multi-processor kernels boot normally ... but in this case we can't use any USB devices which is not really satisfactory. Enabling or disabling hyperthreading in the BIOS doesn't seem to make any difference. The same behavior exists on the same machine with a stock Fedora Core 2 kernel (not sure which version exactly; a colleague tested this) which leads me to believe that this may be a RHEL analogue of bugid 125832. Have tried Dell BIOS version A03 and A04. Dell tech support is not interested in working on this problem. I get the impression they think it's a kernel problem, so that's why I'm submitting this bug report. (Dell has replaced the motherboard, both processors, the scsi cable, and the voltage regulator, so I don't think it's a HW problem.) The very odd part is that the system *will* boot successfully with SMP and USB enabled some small fraction of the time, perhaps once in ten. I have tried all kinds of tests regarding warm vs cold starts, whether I enter the BIOS before starting Linux, etc., but can't find any consistent way to force a successful or failed boot. Probably there is some magic combination but I couldn't find it. Version-Release number of selected component (if applicable): kernel-smp-2.4.21-20.EL How reproducible: Sometimes Steps to Reproduce: 1. enable USB in system BIOS 2. boot SMP kernel 3. Actual Results: System freezes after "booting processor 1/6 eip 2000", or resets following "mptbase: Initiating ioc0 bringup". Expected Results: System boots up all the way. Additional info: I am not sure what log info might be useful; if there's anything that the kernel gurus would like to look at, please let me know.
PeterR, could you please determine if the U4 beta kernel resolves this problem? The kernel version currently in the RHN beta channel is 2.4.21-23.EL, but the -24.EL kernel should appear there within a week. PeteZ implemented USB BIOS-to-kernel hand-off in U4, although there was a recent fix in an error path in the latest U4 respin. PeteZ, would you expect this to be fixed by 0653.zaitcev.early-usb-handoff.patch?
This is likely to be a bug in BIOS emulation of PS/2 ports. If so, proper handoff may help. It is shipping in 2.4.21-20, I'm pretty sure, but it has not be enabled with "usb-handoff" kernel parameter in grub.conf. Failing that, BIOS tweaks are the only answer. Peter wrote that "Emulation" is enabled separately of "Controller", in which case the workaround to try is to disable emulation while leaving the controller enabled. Unfortunately, this is likely to leave GRUB without input; so a UP kernel would be needed to be kept around at all time to fix system if anything goes wrong. Let's see if usb-handoff helps.
I won't be able to get access to this system for a few days, probably, but will give your suggestions a try then. Thanks!!!! -Peter Ruprecht
I have added usb-handoff as a kernel option in grub.conf for 2.4.21-20.EL (smp) and re-enabled USB Emulation and Controller in the BIOS, and the machine now seems to boot normally. I only had time to try booting it twice, but previously it would fail almost every time, so two successive successful boots seems very good. Thanks for your quick responses and working solution!
Closing as NOTABUG according to my understanding that this is actually a BIOS bug (and has now been worked around).
Peter, if you can, please attach the output of "dmidecode" (it's a part of kernel-utils). This should allow us to enable this automatically in the future, without extra options. Do not drop it into comments box - it's going to be rather long.
Created attachment 106625 [details] dmidecode for Dell Precision 650n BIOS A04