[PATCH 2/3] pci/hotplug/pnv-php: Disable surprise hotplug capability on conflicts

[Andrew Donnellan]

On 16/02/17 10:22, Gavin Shan wrote:
> The root port or PCIe switch downstream port might have been associated
> with driver other than pnv-php. The MSI or MSIx might also have been
> enabled by that driver (e.g. pcieport_drv). Attempt to enable MSI incurs
> below backtrace:
>
>  PowerPC PowerNV PCI Hotplug Driver version: 0.1
>  ------------[ cut here ]------------
>  WARNING: CPU: 19 PID: 1004 at drivers/pci/msi.c:1071 \
>                               __pci_enable_msi_range+0x84/0x4e0
>  NIP [c000000000665c34] __pci_enable_msi_range+0x84/0x4e0
>  LR [c000000000665c24] __pci_enable_msi_range+0x74/0x4e0
>  Call Trace:
>  [c000000384d67600] [c000000000665c24] __pci_enable_msi_range+0x74/0x4e0
>  [c000000384d676e0] [d00000000aa31b04] pnv_php_register+0x564/0x5a0 [pnv_php]
>  [c000000384d677c0] [d00000000aa31658] pnv_php_register+0xb8/0x5a0 [pnv_php]
>  [c000000384d678a0] [d00000000aa31658] pnv_php_register+0xb8/0x5a0 [pnv_php]
>  [c000000384d67980] [d00000000aa31dfc] pnv_php_init+0x60/0x98 [pnv_php]
>  [c000000384d679f0] [c00000000000cfdc] do_one_initcall+0x6c/0x1d0
>  [c000000384d67ab0] [c000000000b92354] do_init_module+0x94/0x254
>  [c000000384d67b40] [c00000000019719c] load_module+0x258c/0x2c60
>  [c000000384d67d30] [c000000000197bb0] SyS_finit_module+0xf0/0x170
>  [c000000384d67e30] [c00000000000b184] system_call+0x38/0xe0
> 360aebd85a4c
> This fixes the issue by skipping enabling the surprise hotplug
> capability if the MSI or MSIx on the PCI slot's upstream port has
> been enabled by other driver.
>
> Cc: <stable at vger.kernel.org> # v4.9+
> Fixes: 360aebd85a4c ("drivers/pci/hotplug: Support surprise hotplug in powernv driver")
> Signed-off-by: Gavin Shan <gwshan at linux.vnet.ibm.com>

Should this print something to the kernel log to indicate that surprise 
hotplug is unavailable?

Otherwise:

Reviewed-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>

-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan at au1.ibm.com  IBM Australia Limited