From: "Pali Rohár" <pali@kernel.org>
To: Stefan Roese <sr@denx.de>
Cc: linux-pci@vger.kernel.org, Bjorn Helgaas <helgaas@kernel.org>,
Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com>,
Michal Simek <michal.simek@xilinx.com>,
Yao Hongbo <yaohongbo@linux.alibaba.com>,
Naveen Naidu <naveennaidu479@gmail.com>
Subject: Re: [PATCH v3 2/2] PCI/AER: Enable AER on all PCIe devices supporting it
Date: Thu, 20 Jan 2022 14:23:11 +0100 [thread overview]
Message-ID: <20220120132311.leokj67pvuqsbmnv@pali> (raw)
In-Reply-To: <487c2f8f-a02d-1ddb-ff17-339cbac7e1a7@denx.de>
On Thursday 20 January 2022 08:31:31 Stefan Roese wrote:
> On 1/19/22 11:37, Pali Rohár wrote:
> > On Wednesday 19 January 2022 10:22:00 Stefan Roese wrote:
> > > With this change, AER is now enabled on all PCIe devices, also when the
> > > PCIe device is hot-plugged.
> > >
> > > Please note that this change is quite invasive, as with this patch
> > > applied, AER now will be enabled in the Device Control registers of all
> > > available PCIe Endpoints, which currently is not the case.
> > >
> > > When "pci=noaer" is selected, AER stays disabled of course.
> >
> > Hello Stefan! I was thinking more about this change and I'm not sure
> > what happens if AER-capable PCIe device is hotplugged into some PCIe
> > switch connected in the PCIe hierarchy where Root Port is not
> > AER-capable (e.g. current linux implementation of pci-aardvark.c and
> > pci-mvebu.c). My feeling is that in this case AER should not be enabled
> > as there is nobody who can deliver AER interrupt to the OS. But I really
> > do not know what is supposed from kernel AER driver, so lets wait for
> > Bjorn reply.
>
> But what happens right now, when a device driver like the NVMe driver
> calls pci_enable_pcie_error_reporting() ? There is also no checking,
> if the connected Root Port or some switch / bridge in-between supports
> AER or not. IIUTC, this is identical to what this patch here does.
> Enable AER in the device and if the upstream infrastructure does not
> support AER, then the AER event will just not be received by the
> Kernel. Which is most likely not worse than not enabling AER at all
> on this device. Or am I missing something?
You are right!
Seems that AER code has lot of candidates for followup fixes/cleanups...
> > And when you opened this issue with hotplugging, another thing for
> > followup changes in future is calling pcie_set_ecrc_checking() function
> > to align ECRC state of newly hotplugged device with "pci=ecrc=..."
> > cmdline option. As currently it is done only at that function
> > set_device_error_reporting().
>
> Agreed, this is another area to look into. Not sure if it's okay to
> address this, once this patch-set has been accepted (if it will be).
>
> Thanks,
> Stefan
next prev parent reply other threads:[~2022-01-20 13:23 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-19 9:21 [PATCH v3 0/2] Fully enable AER Stefan Roese
2022-01-19 9:21 ` [PATCH v3 1/2] PCI/portdrv: Don't disable AER reporting in get_port_device_capability() Stefan Roese
2022-01-19 9:22 ` [PATCH v3 2/2] PCI/AER: Enable AER on all PCIe devices supporting it Stefan Roese
2022-01-19 10:37 ` Pali Rohár
2022-01-20 7:31 ` Stefan Roese
2022-01-20 13:23 ` Pali Rohár [this message]
2022-01-20 15:46 ` Bjorn Helgaas
2022-01-20 16:59 ` Stefan Roese
2022-01-20 17:54 ` Bjorn Helgaas
2022-01-19 18:25 ` Keith Busch
2022-01-19 21:00 ` Bjorn Helgaas
2022-01-19 21:18 ` Keith Busch
2022-01-20 7:32 ` Stefan Roese
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