On Wed, Apr 13, 2016 at 10:58:18AM +0100, Sudeep Holla wrote:

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 [off-list ref] wrote:

quoted

On Tue, Jul 28, 2015 at 10:45:26AM -0700, Duc Dang wrote:

quoted

On Tue, Jul 28, 2015 at 9:43 AM, Bjorn Helgaas [off-list ref] wrote:

quoted

On Fri, Jul 24, 2015 at 7:05 PM, Duc Dang [off-list ref] wrote:

quoted

Hi Bjorn,

On Fri, Jul 24, 2015 at 3:42 PM, Bjorn Helgaas [off-list ref] wrote:

quoted

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.

We found that the unhandled faults occurred when using an extender
card.  After removing the extender card, we didn't see the faults any
more.

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