On 04.03.2011 [12:05:29 +1100], Michael Ellerman wrote: > On Thu, 2011-03-03 at 11:39 -0800, Nishanth Aravamudan wrote: > > On upcoming hardware, we have a PCI adapter with two functions, one of > > which uses MSI and the other uses MSI-X. This adapter, when MSI is > > disabled using the "old" firmware interface (RTAS_CHANGE_FN), still > > signals an MSI-X interrupt and triggers an EEH. We are working with the > > vendor to ensure that the hardware is not at fault, but if we use the > > "new" interface (RTAS_CHANGE_MSI_FN) to disable MSI, we also > > automatically disable MSI-X and the adapter does not appear to signal > > any stray MSI-X interrupt. > > It seems this could also be a firmware bug, have we heard anything from > them? PAPR explicitly says that RTAS_CHANGE_FN (function=1) should > disable MSI _and_ MSI-X (R1???7.3.10.5.1???1).
We're tracking that down too. I think the fact that the interrupt is coming in is a hardware bug in this particular adapter. I'm looking at PAPR again and I see what might be a contradiction: 7.3.10.5.1: "To removing all MSIs, set the Requested Number of Interrupts to zero." Table 71: "Function ... 1: Request to set to a new number of MSI or MSI-X (platform choice) interrupts (including set to 0)" It seems like the Table claims that using RTAS_CHANGE_FN with 0, could change only MSI or MSI-X and still be not a bug? It does seem like it should disable both, but from what we've seen with this adapter, it doesn't appear to. > > Signed-off-by: Nishanth Aravamudan <n...@us.ibm.com> > > Cc: Milton Miller <milt...@bga.com> > > Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org> > > Cc: Paul Mackerras <pau...@samba.org> > > Cc: Me :) Sorry! I was in a hurry to get this out the door, my fault. Note, you don't show up per scripts/get_maintainer.pl :) > > diff --git a/arch/powerpc/platforms/pseries/msi.c > > b/arch/powerpc/platforms/pseries/msi.c > > index 1164c34..9434576 100644 > > --- a/arch/powerpc/platforms/pseries/msi.c > > +++ b/arch/powerpc/platforms/pseries/msi.c > > @@ -93,8 +93,18 @@ static void rtas_disable_msi(struct pci_dev *pdev) > > if (!pdn) > > return; > > > > - if (rtas_change_msi(pdn, RTAS_CHANGE_FN, 0) != 0) > > - pr_debug("rtas_msi: Setting MSIs to 0 failed!\n"); > > + /* > > + * disabling MSI with the explicit interface also disables MSI-X > > + */ > > + if (rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, 0) != 0) { > > + /* > > + * may have failed due to lacking > > + * "ibm,change-msix-capable" property > > + */ > > + if (rtas_change_msi(pdn, RTAS_CHANGE_FN, 0) != 0) { > > + pr_debug("rtas_msi: Setting MSIs to 0 failed!\n"); > > + } > > + } > > } > > This is probably a pretty safe change anyway, ie. use the newer API if > it is present. The comment is backward though, the call fails because > the new interface is not implemented, and that fact is signalled by the > absence of the property. Updated the comment, thanks: On upcoming hardware, we have a PCI adapter with two functions, one of which uses MSI and the other uses MSI-X. This adapter, when MSI is disabled using the "old" firmware interface (RTAS_CHANGE_FN), still signals an MSI-X interrupt and triggers an EEH. We are working with the vendor to ensure that the hardware is not at fault, but if we use the "new" interface (RTAS_CHANGE_MSI_FN) to disable MSI, we also automatically disable MSI-X and the adapter does not appear to signal any stray MSI-X interrupt. Signed-off-by: Nishanth Aravamudan <n...@us.ibm.com> --- arch/powerpc/platforms/pseries/msi.c | 14 ++++++++++++-- 1 files changed, 12 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/platforms/pseries/msi.c b/arch/powerpc/platforms/pseries/msi.c index 1164c34..18ac801 100644 --- a/arch/powerpc/platforms/pseries/msi.c +++ b/arch/powerpc/platforms/pseries/msi.c @@ -93,8 +93,18 @@ static void rtas_disable_msi(struct pci_dev *pdev) if (!pdn) return; - if (rtas_change_msi(pdn, RTAS_CHANGE_FN, 0) != 0) - pr_debug("rtas_msi: Setting MSIs to 0 failed!\n"); + /* + * disabling MSI with the explicit interface also disables MSI-X + */ + if (rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, 0) != 0) { + /* + * may have failed because explicit interface is not + * present + */ + if (rtas_change_msi(pdn, RTAS_CHANGE_FN, 0) != 0) { + pr_debug("rtas_msi: Setting MSIs to 0 failed!\n"); + } + } } static int rtas_query_irq_number(struct pci_dn *pdn, int offset) -- 1.7.1 _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev