On Wed, Dec 08, 2010 at 11:44:23AM -0500, Vivek Goyal wrote: > On Wed, Dec 08, 2010 at 09:47:48AM -0500, Neil Horman wrote: > > I wrote this quirk awhile ago to properly setup MCP55 chips on > > hypertransport > > busses so that interrupts reached whatever cpu happend to boot the kdump > > kernel. > > while that works well, it was recently shown to me that a a > > non-hypertransport > > variant of the MCP55 exists, and on those system the register that this > > quirk > > manipulates causes hangs if you write to it. Since the quirk was only > > meant to > > handle errors found on MCP55 chips that have a HT interface, this patch > > adds a > > filter to make sure the chip is an HT capable before making the needed > > register > > adjustment. This lets the broken MCP55s work with kdump while not breaking > > the > > non-HT variants. > > > > So Neil, with non hypertransport MCP55s, interrupts are delivered to > all the cpus and seond kernel still boots? > I cannot guarantee that. All that I can guarantee is that, on MCP55 chips without hypertransport capability, the register which is used to configure interrupt delivery is either non-existant, or different in such a way that writing to it results in a hang on the boot of the initial kernel. So this quirk has no effect on kdumps behavior regardless of the interrupt delivery behavior on such variants of the chip. I would presume however, given that this register is so different that interrupts would be delivered to all cpus, as one would expect. Mathieu, since you have the affected hardware, could you attempt to preform a kexec operation and tell us for certain? Thanks! Neil
> Acked-by: Vivek Goyal <[email protected]> > > Thanks > Vivek > > > Resolves https://bugzilla.kernel.org/show_bug.cgi?id=23952 > > > > Tested successfully by the reporter and myself. > > > > Reported-by: Mathieu Bérard <[email protected]> > > CC: [email protected] > > CC: [email protected] > > CC: Vivek Goyal <[email protected]> > > CC: Jesse Barnes <[email protected]> > > Signed-off-by: Neil Horman <[email protected]> > > --- > > drivers/pci/quirks.c | 3 +++ > > 1 files changed, 3 insertions(+), 0 deletions(-) > > > > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c > > index 6f9350c..313c0bd 100644 > > --- a/drivers/pci/quirks.c > > +++ b/drivers/pci/quirks.c > > @@ -2329,6 +2329,9 @@ static void __devinit > > nvbridge_check_legacy_irq_routing(struct pci_dev *dev) > > { > > u32 cfg; > > > > + if (!pci_find_capability(dev, PCI_CAP_ID_HT)) > > + return; > > + > > pci_read_config_dword(dev, 0x74, &cfg); > > > > if (cfg & ((1 << 2) | (1 << 15))) { > > -- > > 1.7.2.3 > > _______________________________________________ > kexec mailing list > [email protected] > http://lists.infradead.org/mailman/listinfo/kexec _______________________________________________ kexec mailing list [email protected] http://lists.infradead.org/mailman/listinfo/kexec
