On Sun, 9 Aug 2015, Jiang Liu wrote: > Nick Meier reported a regression with HyperV that " > After rebooting the VM, the following messages are logged in syslog > when trying to load the tulip driver: > tulip: Linux Tulip drivers version 1.1.15 (Feb 27, 2007) > tulip: 0000:00:0a.0: PCI INT A: failed to register GSI > tulip: Cannot enable tulip board #0, aborting > tulip: probe of 0000:00:0a.0 failed with error -16 > Errors occur in 3.19.0 kernel > Works in 3.17 kernel. > " > > According to the ACPI dump file posted by Nick at > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1440072 > > The ACPI MADT table includes an interrupt source overridden entry for > ACPI SCI: > [236h 0566 1] Subtable Type : 02 <Interrupt Source Override> > [237h 0567 1] Length : 0A > [238h 0568 1] Bus : 00 > [239h 0569 1] Source : 09 > [23Ah 0570 4] Interrupt : 00000009 > [23Eh 0574 2] Flags (decoded below) : 000D > Polarity : 1 > Trigger Mode : 3 > That means ACPI SCI interrupt(Interrupt : 00000009) works in > level(Trigger Mode : 3), high(Polarity : 1) mode. > > And in DSDT table, we have _PRT method to define PCI interrupts, which > eventually goes to: > Name (PRSA, ResourceTemplate () > { > IRQ (Level, ActiveLow, Shared, ) > {3,4,5,7,9,10,11,12,14,15} > }) > Name (PRSB, ResourceTemplate () > { > IRQ (Level, ActiveLow, Shared, ) > {3,4,5,7,9,10,11,12,14,15} > }) > Name (PRSC, ResourceTemplate () > { > IRQ (Level, ActiveLow, Shared, ) > {3,4,5,7,9,10,11,12,14,15} > }) > Name (PRSD, ResourceTemplate () > { > IRQ (Level, ActiveLow, Shared, ) > {3,4,5,7,9,10,11,12,14,15} > }) > which means it's also possible to use IRQ9 for PCI interrupt, but works > in Level, ActiveLow mode. So it conflicts with ACPI SCI interrupt source > overriddern. > > So implement a quirk to correct interrupt attribute for HyperV SCI > interrupt. Nick reports the proposed patch fixes the regression as " > Applied the above proposed patch with the DMI values substituted. > The tulip driver loaded, and an address was assigned via DHCP. > " > Please refer to following links for more information: > https://bugzilla.kernel.org/show_bug.cgi?id=101301 > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1440072 > > Fixes: cd68f6bd53cf ("x86, irq, acpi: Get rid of special handling of GSI for ACPI SCI") I have a hard time to understand WHY that particular patch actually caused that regression, WHY the original code worked with this weird ACPI table and WHY we are better off with a quirk for this case. Can you please elaborate? Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
