Re: What is ENXIO – MSI allocation regression in :[Was Re: svn commit: r321714 - in head/sys/dev: mpr mps]

[Scott Long]

> On Jun 4, 2018, at 4:51 AM, Harry Schmalzbauer <freebsd at omnilan.de> wrote:
> 
> Am 01.08.2017 um 11:40 schrieb Harry Schmalzbauer:
>> Bezüglich Scott Long's Nachricht vom 31.07.2017 18:56 (localtime):
>> 
>> …
>>>> I'd like to report one I hadn't expected:
>>>> 
>>>> mps0: <Avago Technologies (LSI) SAS2008> port 0x4000-0x40ff mem 0xc3bc0000-0xc3bc3fff,0xc3b80000-0xc3bbffff irq 19 at device 0.0 on pci7
>>>> 
>>>> mps0: Firmware: 20.00.04.00, Driver: 21.02.00.00-fbsd
>>>> mps0: IOCCapabilities:
>>>> 185c<ScsiTaskFull,DiagTrace,SnapBuf,EEDP,TransRetry,IR>
>>>> mps0: Cannot allocate INTx interrupt
>>>> mps0: mps_iocfacts_allocate failed to setup interrupts
>>>> mps0: mps_attach IOC Facts based allocation failed with error 6
>>>> panic: resource_list_release: resource entry is not busy
>>>> cpuid = 6
>>>> KDB: stack backtrace:
>>>> #0 0xffffffff805e32d7 at kdb_backtrace+0x67
>>>> #1 0xffffffff805a1d26 at vpanic+0x186
>>>> #2 0xffffffff805a1b93 at panic+0x43
>>>> #3 0xffffffff805d71c6 at resource_list_release+0x1c6
>>>> #4 0xffffffff8040fef1 at mps_pci_free+0xe1
>>>> #5 0xffffffff8040fa23 at mps_pci_attach+0x1b3
>>>> #6 0xffffffff805d6594 at device_attach+0x3a4
>>>> #7 0xffffffff805d774d at bus_generic_attach+0x3d
>>>> #8 0xffffffff8044ac05 at pci_attach+0xd5
>>>> #9 0xffffffff805d6594 at device_attach+0x3a4
>>>> #10 0xffffffff805d774d at bus_generic_attach+0x3d
>>>> #11 0xffffffff80364761 at acpi_pcib_pci_attach+0xa1
>>>> #12 0xffffffff805d6594 at device_attach+0x3a4
>>>> #13 0xffffffff805d774d at bus_generic_attach+0x3d
>>>> #14 0xffffffff8044ac05 at pci_attach+0xd5
>>>> #15 0xffffffff805d6594 at device_attach+0x3a4
>>>> #16 0xffffffff805d774d at bus_generic_attach+0x3d
>>>> #17 0xffffffff80363e4d at acpi_pcib_acpi_attach+0x42d
>>>> Uptime: 1s
>> …
>> 
>>> Fixed in r321799, thanks for the report.
>> Fix confiremd; merged together with r321733 (and 321737) to 11.1 and
>> panic vanished.
> 
> Late in the 11.2 phase, I identified this commit as a regression for MSI (non-x) alloctaion.
> I have an idea what probably causes the problem here (INTx allocation, although MSI (and MSI-x) capability):
> disable_msix is not 0 (I need to disable MSI-x because of ESXi-passthru…).
> 
> Corresponding lines:
> {
>         device_t dev;
>         int error, msgs;
> 
>         dev = sc->mps_dev;
>         error = 0;
>         msgs = 0;
> 
>         if ((sc->disable_msix == 0) &&
>             ((msgs = pci_msix_count(dev)) >= MPS_MSI_COUNT))
>                 error = mps_alloc_msix(sc, MPS_MSI_COUNT);
>         if ((error != 0) && (sc->disable_msi == 0) &&
>             ((msgs = pci_msi_count(dev)) >= MPS_MSI_COUNT))
>                 error = mps_alloc_msi(sc, MPS_MSI_COUNT);
>         if (error != 0)
>                 msgs = 0;
> 
>         sc->msi_msgs = msgs;
>         return (error);
> }
> 
> Before r321714, error was assigned ENXIO, which, if != 0, could help make me understand the problem.
> Unfortunately I have no idea what ENXIO means, where it's defined and most important, how to find the place where the declaration/definition happens.  Only joe and vi available here, any hints highly appreciated.
> 
> I can confirm that MSI allocation works with mps.ko_21.02.00.00-fbsd-r321415 with my ESXi-passthru-non_msi-x setup.
> Although the dirver emits no message that an MSI was allocated, like toher drivers do.  That's a cosmetic one though.
> But the MSI->INTx regression is a severe one for me, which I'd like to fix myself but I'm missing so many fundamental skills :-(
> 

Hi Harry,

You are correct about the bug.  Please change the line at the top of the function that reads

error = 0;

to

error = ENXIO;

Let me know if that fixes the MSI problem for you.

Scott