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From: Stefan Roese <sr@denx.de>
To: linux-pci@vger.kernel.org
Cc: Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com>,
	Michal Simek <michal.simek@xilinx.com>
Subject: pcie-xilinx-nwl: Uncorrectable errors upon PCIe surprise removal
Date: Thu, 27 May 2021 10:47:15 +0200	[thread overview]
Message-ID: <61d5c2d1-d5a3-f074-c81a-b972840b3536@denx.de> (raw)

Hi,

on our ZynqMP platform we are seeing uncorrectable errors when we try
to access the BAR of a PCIe device (NVMe drive) which was removed
(surprise removal):

[  255.743801] nwl-pcie fd0e0000.pcie: Slave error
[  255.745210] nwl-pcie fd0e0000.pcie: Non-Fatal Error in AER Capability
[  255.750714] nwl-pcie fd0e0000.pcie: Non-Fatal Error Detected
[  255.752523] nwl-pcie fd0e0000.pcie: Non-Fatal Error in AER Capability
[  255.753840] nwl-pcie fd0e0000.pcie: Non-Fatal Error Detected
[  255.755174] nwl-pcie fd0e0000.pcie: Non-Fatal Error in AER Capability
[  255.756706] nwl-pcie fd0e0000.pcie: Non-Fatal Error Detected
[  255.758168] nwl-pcie fd0e0000.pcie: Non-Fatal Error in AER Capability
...

Sometimes even accompanied (started) by a Kernel crash:

Internal error: synchronous external abort: 96000210 [#1] SMP

It seems that the "Slave error" (bit 4) can be cleared in
nwl_pcie_misc_handler() but both other "Non-Fatal" errors not.

I'm wondering now, if this situation can be resolved somehow, so that
the system "survives" such surprise removals without a crash. What we
really would like to see is, that reading from the unavailable PCI space
(BAR area) returns 0xffffffff as common for PCI.

So is this a known issue that accesses to BAR ranges of removed PCIe
devices result in such errors? If yes, why is this the case? Is there
perhaps a way to fully clear the error condition?

Thanks,
Stefan

                 reply	other threads:[~2021-05-27  8:47 UTC|newest]

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