No bus number available for hot-added bridge

No bus number available for hot-added bridge

[Kallol Biswas]

Hi,
   I have been trying to hot-add a PCIe bridge and getting the
following message in dmesg:

No bus number available for hot-added bridge 0000:06:00.

The kernel is 4.4. Do we have any patch for this?  I tried Yinghai's
for-pci-busn-alloc patch. Did not work. Not sure I picked up the right
changes.

Any input...

[  793.982780] pciehp 0000:05:00.0:pcie24: pciehp_check_link_active:
lnk_status = a103
[  793.982783] pciehp 0000:05:00.0:pcie24: slot(0-1): Link Up event
[  793.982815] pciehp 0000:05:00.0:pcie24: pciehp_get_power_status:
SLOTCTRL 80 value read 1571
[  793.982835] pciehp 0000:05:00.0:pcie24: pending interrupts 0x0010
from Slot Status
[  793.982841] pciehp 0000:05:00.0:pcie24: pciehp_power_on_slot:
SLOTCTRL 80 write cmd 0
[  793.982847] pciehp 0000:05:00.0:pcie24: __pciehp_link_set: lnk_ctrl = 0
[  793.982859] pciehp 0000:05:00.0:pcie24: pending interrupts 0x0010
from Slot Status
[  793.982865] pciehp 0000:05:00.0:pcie24: pciehp_green_led_blink:
SLOTCTRL 80 write cmd 200
[  793.982871] pciehp 0000:05:00.0:pcie24: pciehp_check_link_active:
lnk_status = a103
[  794.085818] pciehp 0000:05:00.0:pcie24: pciehp_check_link_status:
lnk_status = a103
[  794.085909] pci 0000:06:00.0: [10b5:9797] type 01 class 0x060400
[  794.086232] pci 0000:06:00.0: Max Payload Size set to 256 (was 128, max 512)
[  794.086563] pci 0000:06:00.0: PME# supported from D0 D3hot D3cold
[  794.086884] iommu: Adding device 0000:06:00.0 to group 47
[  794.093797] No bus number available for hot-added bridge 0000:06:00.0
[  794.093816] pcieport 0000:05:00.0: PCI bridge to [bus 06]
[  794.093822] pcieport 0000:05:00.0:   bridge window [io  0x1000-0x1fff]
[  794.093829] pcieport 0000:05:00.0:   bridge window [mem
0xc8000000-0xc83fffff]
[  794.093835] pcieport 0000:05:00.0:   bridge window [mem
0x280000000-0x2801fffff 64bit pref]
[  794.094364] pciehp 0000:05:00.0:pcie24: pending interrupts 0x0010
from Slot Status
[  794.094369] pciehp 0000:05:00.0:pcie24: pciehp_green_led_on:
SLOTCTRL 80 write cmd 100

Re: No bus number available for hot-added bridge

[Bjorn Helgaas]

On Fri, Jul 15, 2016 at 01:33:32PM -0700, Kallol Biswas wrote:
> Hi,
>    I have been trying to hot-add a PCIe bridge and getting the
> following message in dmesg:
> 
> No bus number available for hot-added bridge 0000:06:00.
> 
> The kernel is 4.4. Do we have any patch for this?  I tried Yinghai's
> for-pci-busn-alloc patch. Did not work. Not sure I picked up the right
> changes.

As far as I know there is not a patch for this.  We probably should
reserve some bus number space just like we do for memory and I/O
space, but I don't think we do that today.

One workaround would be to have firmware configure the upstream
bridges (05:00.0 and the path leading to it) with larger bus number
apertures.

> [  793.982780] pciehp 0000:05:00.0:pcie24: pciehp_check_link_active:
> lnk_status = a103
> [  793.982783] pciehp 0000:05:00.0:pcie24: slot(0-1): Link Up event
> [  793.982815] pciehp 0000:05:00.0:pcie24: pciehp_get_power_status:
> SLOTCTRL 80 value read 1571
> [  793.982835] pciehp 0000:05:00.0:pcie24: pending interrupts 0x0010
> from Slot Status
> [  793.982841] pciehp 0000:05:00.0:pcie24: pciehp_power_on_slot:
> SLOTCTRL 80 write cmd 0
> [  793.982847] pciehp 0000:05:00.0:pcie24: __pciehp_link_set: lnk_ctrl = 0
> [  793.982859] pciehp 0000:05:00.0:pcie24: pending interrupts 0x0010
> from Slot Status
> [  793.982865] pciehp 0000:05:00.0:pcie24: pciehp_green_led_blink:
> SLOTCTRL 80 write cmd 200
> [  793.982871] pciehp 0000:05:00.0:pcie24: pciehp_check_link_active:
> lnk_status = a103
> [  794.085818] pciehp 0000:05:00.0:pcie24: pciehp_check_link_status:
> lnk_status = a103
> [  794.085909] pci 0000:06:00.0: [10b5:9797] type 01 class 0x060400
> [  794.086232] pci 0000:06:00.0: Max Payload Size set to 256 (was 128, max 512)
> [  794.086563] pci 0000:06:00.0: PME# supported from D0 D3hot D3cold
> [  794.086884] iommu: Adding device 0000:06:00.0 to group 47
> [  794.093797] No bus number available for hot-added bridge 0000:06:00.0
> [  794.093816] pcieport 0000:05:00.0: PCI bridge to [bus 06]
> [  794.093822] pcieport 0000:05:00.0:   bridge window [io  0x1000-0x1fff]
> [  794.093829] pcieport 0000:05:00.0:   bridge window [mem
> 0xc8000000-0xc83fffff]
> [  794.093835] pcieport 0000:05:00.0:   bridge window [mem
> 0x280000000-0x2801fffff 64bit pref]
> [  794.094364] pciehp 0000:05:00.0:pcie24: pending interrupts 0x0010
> from Slot Status
> [  794.094369] pciehp 0000:05:00.0:pcie24: pciehp_green_led_on:
> SLOTCTRL 80 write cmd 100
> --
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Re: No bus number available for hot-added bridge

[Yinghai Lu]

On Fri, Jul 15, 2016 at 1:33 PM, Kallol Biswas <kallol@nucleodyne.com> wrote:
> Hi,
>    I have been trying to hot-add a PCIe bridge and getting the
> following message in dmesg:
>
> No bus number available for hot-added bridge 0000:06:00.
>
> The kernel is 4.4. Do we have any patch for this?  I tried Yinghai's
> for-pci-busn-alloc patch. Did not work. Not sure I picked up the right
> changes.
>
> Any input...
>
> [  794.085909] pci 0000:06:00.0: [10b5:9797] type 01 class 0x060400
> [  794.086232] pci 0000:06:00.0: Max Payload Size set to 256 (was 128, max 512)
> [  794.086563] pci 0000:06:00.0: PME# supported from D0 D3hot D3cold
> [  794.086884] iommu: Adding device 0000:06:00.0 to group 47
> [  794.093797] No bus number available for hot-added bridge 0000:06:00.0


Can you please send out the whole boot log with
CONFIG_PCI_DEBUG=y ?

also output for lspci -tv and lspci -vvxxx.

Thanks

Yinghai

Re: No bus number available for hot-added bridge

[Kallol Biswas]

Thank you very much for response.


I have worked around the failure by manually allocating bus number,
and memory bar window for a specific downstream port.


I will send you the logs when I get back to this issue again.
Thank you very much for response.



On Fri, Jul 22, 2016 at 2:17 PM, Yinghai Lu <yinghai@kernel.org> wrote:
> On Fri, Jul 15, 2016 at 1:33 PM, Kallol Biswas <kallol@nucleodyne.com> wrote:
>> Hi,
>>    I have been trying to hot-add a PCIe bridge and getting the
>> following message in dmesg:
>>
>> No bus number available for hot-added bridge 0000:06:00.
>>
>> The kernel is 4.4. Do we have any patch for this?  I tried Yinghai's
>> for-pci-busn-alloc patch. Did not work. Not sure I picked up the right
>> changes.
>>
>> Any input...
>>
>> [  794.085909] pci 0000:06:00.0: [10b5:9797] type 01 class 0x060400
>> [  794.086232] pci 0000:06:00.0: Max Payload Size set to 256 (was 128, max 512)
>> [  794.086563] pci 0000:06:00.0: PME# supported from D0 D3hot D3cold
>> [  794.086884] iommu: Adding device 0000:06:00.0 to group 47
>> [  794.093797] No bus number available for hot-added bridge 0000:06:00.0
>
>
> Can you please send out the whole boot log with
> CONFIG_PCI_DEBUG=y ?
>
> also output for lspci -tv and lspci -vvxxx.
>
> Thanks
>
> Yinghai