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1e75b31d63
In the kdump scenario mentioned below, we can have a case where the device using level triggered interrupt will not generate any interrupts in the kdump kernel. 1. IO-APIC sends a level triggered interrupt to the CPU's local APIC. 2. Kernel crashed before the CPU services this interrupt, leaving the remote-IRR in the IO-APIC set. 3. kdump kernel boot sequence does clear_IO_APIC() as part of IO-APIC initialization. But this fails to reset remote-IRR bit of the IO-APIC RTE as the remote-IRR bit is read-only. 4. Device using that level triggered entry can't generate any more interrupts because of the remote-IRR bit. In clear_IO_APIC_pin(), check if the remote-IRR bit is set and if so do an explicit attempt to clear it (by doing EOI write on modern io-apic's and changing trigger mode to edge/level on older io-apic's). Also before doing the explicit EOI to the io-apic, ensure that the trigger mode is indeed set to level. This will enable the explicit EOI to the io-apic to reset the remote-IRR bit. Tested-by: Leonardo Chiquitto <lchiquitto@novell.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Fixes: https://bugzilla.novell.com/show_bug.cgi?id=701686 Cc: Rafael Wysocki <rjw@novell.com> Cc: Maciej W. Rozycki <macro@linux-mips.org> Cc: Thomas Renninger <trenn@suse.de> Cc: jbeulich@novell.com Cc: yinghai@kernel.org Link: http://lkml.kernel.org/r/20110825190657.157502602@sbsiddha-desk.sc.intel.com Signed-off-by: Ingo Molnar <mingo@elte.hu> |
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| .. | ||
| boot | ||
| configs | ||
| crypto | ||
| ia32 | ||
| include/asm | ||
| kernel | ||
| kvm | ||
| lguest | ||
| lib | ||
| math-emu | ||
| mm | ||
| net | ||
| oprofile | ||
| pci | ||
| platform | ||
| power | ||
| tools | ||
| vdso | ||
| video | ||
| xen | ||
| .gitignore | ||
| Kbuild | ||
| Kconfig | ||
| Kconfig.cpu | ||
| Kconfig.debug | ||
| Makefile | ||
| Makefile_32.cpu | ||