Messages in this thread | | | Date | Sat, 29 Dec 2007 13:19:40 +0200 | From | Eduard-Gabriel Munteanu <> | Subject | Re: [PATCH] Option to disable AMD C1E (allows dynticks to work) |
| |
On Sat, 29 Dec 2007 04:09:41 -0500 Richard Harman <richard@richardharman.com> wrote:
> Right now, with your patch and the 'noirqdebug' option or disabling > nohz the system appears to be stable. This laptop otherwise locks up > trying to configure apic/lapic, or locks up solid later with NO > oops/bug and nothing will bring it out of it (eg, sysrq has no > effect). NMI watchdog was also inoperable, which I believe was due > to the apic/lapic being disabled. > > With your patch, the lapic is used: > > ACPI: LAPIC (acpi_id[0x00] lapic_id[0x00] enabled) > ACPI: LAPIC (acpi_id[0x01] lapic_id[0x01] enabled)
The kernel should display these messages even without my patch.
> These kernel dmesg logs are hand-transcribed, and are from 2.6.22.5, > but this shows where the kernel would lock up good and solid: > > http://www.richardharman.com/pavilion/2.6.22.5/dmesg.txt
I doubt it is my patch that makes your laptop work. C1E detection was added by the following commit:
$ git-describe fb79d22e1d4b06385796cc0db0084a2e07beccee v2.6.23-2294-gfb79d22
Try building a 2.6.24-rc6 without my patch and see if it still works (apply it again in reverse mode, for example). I guess it will work, because the kernel shouldn't use the LAPIC as a timer at all (except as a dummy one), with or without dynticks support.
When I started investigating the "nohz is not working problem", I stumbled across a few threads on LKML where a few people had similar problems with their laptops and they where instructed to pass "nolapic" or something similar as a boot parameter to the kernel. I guess the problem disappeared after the commit I mentioned previously, since such reports weren't that recent. IIRC, that was on kernels previous to 2.6.24-*, where x86 and x86-64 weren't unified and there were no dynticks on the latter.
To be more clear, my patch disables C1E instead of disabling the LAPIC, as these two don't agree with each other.
| |