X-Gene: Unhandled fault: synchronous external abort in pci_generic_config_read32

[Sudeep Holla]

Hi,

(sorry for replying on the old thread, but I found it could be related
to the issue
I have now)

On Tue, Jul 28, 2015 at 10:29 PM, Bjorn Helgaas <bhelgaas at google.com> wrote:
> On Tue, Jul 28, 2015 at 10:45:26AM -0700, Duc Dang wrote:
>> On Tue, Jul 28, 2015 at 9:43 AM, Bjorn Helgaas <bhelgaas at google.com> wrote:
>> > On Fri, Jul 24, 2015 at 7:05 PM, Duc Dang <dhdang at apm.com> wrote:
>> >> Hi Bjorn,
>> >>
>> >> On Fri, Jul 24, 2015 at 3:42 PM, Bjorn Helgaas <bhelgaas at google.com> wrote:
>> >>>
>> >>> I regularly see faults like this on an APM X-Gene:
>> >>>
>> >>>   U-Boot 2013.04-mustang_sw_1.14.14 (Dec 16 2014 - 15:59:33)
>> >>>   CPU0: APM ARM 64-bit Potenza Rev B0 2400MHz PCP 2400MHz
>> >>>        32 KB ICACHE, 32 KB DCACHE
>> >>>        SOC 2000MHz IOBAXI 400MHz AXI 250MHz AHB 200MHz GFC 125MHz
>> >>>   ...
>> >>>   Unhandled fault: synchronous external abort (0x96000010) at 0xffffff8000110034
>> >>>   Internal error: : 96000010 [#1] SMP
>> >>>   Modules linked in:
>> >>>   CPU: 0 PID: 3723 Comm: ... 4.1.0-smp-DEV #3
>> >>>   Hardware name: APM X-Gene Mustang board (DT)
>> >>>   task: ffffffc7dc1a4140 ti: ffffffc7dc118000 task.ti: ffffffc7dc118000
>> >>>   PC is at pci_generic_config_read32+0x4c/0xb8
>> >>>   LR is at pci_generic_config_read32+0x40/0xb8
>> >>>   pc : [<ffffffc00033b90c>] lr : [<ffffffc00033b900>] pstate: 600001c5
>> >>>   ...
>> >>>   Call trace:
>> >>>   [<ffffffc00033b90c>] pci_generic_config_read32+0x4c/0xb8
>> >>>   [<ffffffc00033bf58>] pci_user_read_config_byte+0x60/0xc4
>> >>>   [<ffffffc0003496a8>] pci_read_config+0x15c/0x238
>> >>>   [<ffffffc0002393b4>] sysfs_kf_bin_read+0x68/0xa0
>> >>>   [<ffffffc00023896c>] kernfs_fop_read+0x9c/0x1ac
>> >>>   [<ffffffc0001c361c>] __vfs_read+0x44/0x128
>> >>>   [<ffffffc0001c3e28>] vfs_read+0x84/0x144
>> >>>   [<ffffffc0001c4764>] SyS_read+0x50/0xb0
>> >>
>> >> The log shows kernel gets an exception when trying to access Mellanox
>> >> card configuration space. This is usually due to suboptimal PCIe
>> >> SerDes parameters are using in your board, which will cause bad link
>> >> quality.
>> >> The PCIe SerDes programming is done in U-Boot, so I suggest you do a
>> >> U-Boot upgrade to our latest X-Gene U-Boot release.
>> >
>> > I installed U-Boot 1.15.12, which I thought was the latest.  I'm still
>> > seeing this issue regularly, approx once/hour.
>>
>> Our latest U-Boot is 1.15.15, but U-Boot 1.15.12 is already a good
>> version to use. Are you running any PCIe traffic test when the error
>> happens?
>
> Nope, the machine was either idle or running a reboot test; no PCIe stress
> test or anything.
>

Was there any conclusion on this ?
I am having similar issue[1] on my Juno with sky2 PCIe driver during reboot.

Regards,
Sudeep

[1] http://marc.info/?l=linux-netdev&m=146046999701956&w=2