pcieport AER error spam on Intel Skylake

[Daniel Drake]

Hi,

Working with a sample for a new laptop based on Intel Skylake, the
kernel logs are full of these messages:

pcieport 0000:00:1c.5: AER: Corrected error received: id=00e5
pcieport 0000:00:1c.5: PCIe Bus Error: severity=Corrected,
type=Physical Layer, id=00e5(Receiver ID)
pcieport 0000:00:1c.5: device [8086:9d15] error status/mask=00000001/00002000
pcieport 0000:00:1c.5: [ 0] Receiver Error (First)
pcieport 0000:00:1c.5: AER: Corrected error received: id=00e5
pcieport 0000:00:1c.5: PCIe Bus Error: severity=Corrected,
type=Physical Layer, id=00e5(Receiver ID)
pcieport 0000:00:1c.5: device [8086:9d15] error status/mask=00000001/00002000
pcieport 0000:00:1c.5: [ 0] Receiver Error (First)
pcieport 0000:00:1c.5: AER: Corrected error received: id=00e5
pcieport 0000:00:1c.5: can't find device of ID00e5

Reproduced on 4.2 and on linus master as of today, using x86_64_defconfig.

Apart from the log spam, there is no user-visible effect that I'm
aware of. Booting with pci=nomsi makes the messages go away.

Any thoughts, is this something worth looking into in more detail?

full dmesg: https://gist.github.com/dsd/1d7f738e917465edf2ae
lspci dump: https://gist.github.com/dsd/dc2481d64aadd520b0b3

Thanks,
Daniel
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[Bjorn Helgaas]

Post by Daniel Drake
Hi,
Working with a sample for a new laptop based on Intel Skylake, the
pcieport 0000:00:1c.5: AER: Corrected error received: id=00e5
pcieport 0000:00:1c.5: PCIe Bus Error: severity=Corrected,
type=Physical Layer, id=00e5(Receiver ID)
pcieport 0000:00:1c.5: device [8086:9d15] error status/mask=00000001/00002000
pcieport 0000:00:1c.5: [ 0] Receiver Error (First)
pcieport 0000:00:1c.5: AER: Corrected error received: id=00e5
pcieport 0000:00:1c.5: PCIe Bus Error: severity=Corrected,
type=Physical Layer, id=00e5(Receiver ID)
pcieport 0000:00:1c.5: device [8086:9d15] error status/mask=00000001/00002000
pcieport 0000:00:1c.5: [ 0] Receiver Error (First)
pcieport 0000:00:1c.5: AER: Corrected error received: id=00e5
pcieport 0000:00:1c.5: can't find device of ID00e5
Reproduced on 4.2 and on linus master as of today, using x86_64_defconfig.
Apart from the log spam, there is no user-visible effect that I'm
aware of. Booting with pci=nomsi makes the messages go away.
Any thoughts, is this something worth looking into in more detail?
full dmesg: https://gist.github.com/dsd/1d7f738e917465edf2ae
lspci dump: https://gist.github.com/dsd/dc2481d64aadd520b0b3

Thanks, Daniel, this is indeed really annoying and worth looking into.
Do you happen to know whether it's a regression? We haven't changed
much in AER recently, but it's possible we broke something.

Even if it's not a regression, the output seems a bit wordy and redundant.

Bjorn
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[Alexander Duyck]

Post by Bjorn Helgaas

Post by Daniel Drake
Hi,
Working with a sample for a new laptop based on Intel Skylake, the
pcieport 0000:00:1c.5: AER: Corrected error received: id=00e5
pcieport 0000:00:1c.5: PCIe Bus Error: severity=Corrected,
type=Physical Layer, id=00e5(Receiver ID)
pcieport 0000:00:1c.5: device [8086:9d15] error status/mask=00000001/00002000
pcieport 0000:00:1c.5: [ 0] Receiver Error (First)
pcieport 0000:00:1c.5: AER: Corrected error received: id=00e5
pcieport 0000:00:1c.5: PCIe Bus Error: severity=Corrected,
type=Physical Layer, id=00e5(Receiver ID)
pcieport 0000:00:1c.5: device [8086:9d15] error status/mask=00000001/00002000
pcieport 0000:00:1c.5: [ 0] Receiver Error (First)
pcieport 0000:00:1c.5: AER: Corrected error received: id=00e5
pcieport 0000:00:1c.5: can't find device of ID00e5
Reproduced on 4.2 and on linus master as of today, using x86_64_defconfig.
Apart from the log spam, there is no user-visible effect that I'm
aware of. Booting with pci=nomsi makes the messages go away.
Any thoughts, is this something worth looking into in more detail?
full dmesg: https://gist.github.com/dsd/1d7f738e917465edf2ae
lspci dump: https://gist.github.com/dsd/dc2481d64aadd520b0b3

Thanks, Daniel, this is indeed really annoying and worth looking into.
Do you happen to know whether it's a regression? We haven't changed
much in AER recently, but it's possible we broke something.
Even if it's not a regression, the output seems a bit wordy and redundant.
Bjorn

Since it is correctable errors it is likely some sort of signalling
issue. Could we get the output of something like an lspci -vt? Then you
would be able to tell what the device is on the other side of the link
from 00:1c.5 and then we could probably check to see if there has been
any changes for the device driver on the other end of the link.

My suspicion since this is a laptop is that something like a power
management change might be responsible if this is a regression as I have
seen messages like this pop up as a result of ASPM being enabled before.

- Alex
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[Daniel Drake]

On Wed, Sep 2, 2015 at 7:57 PM, Alexander Duyck

Since it is correctable errors it is likely some sort of signalling issue.
Could we get the output of something like an lspci -vt? Then you would be
able to tell what the device is on the other side of the link from 00:1c.5
and then we could probably check to see if there has been any changes for
the device driver on the other end of the link.

"lspci -vt" reliably causes one occurance of the message, which is
logged by the kernel before lspci has written anything to stdout.
pcieport 0000:00:1c.5: AER: Corrected error received: id=00e5
pcieport 0000:00:1c.5: PCIe Bus Error: severity=Corrected,
type=Physical Layer, id=00e5(Receiver ID)
pcieport 0000:00:1c.5: device [8086:9d15] error status/mask=00000001/00002000
pcieport 0000:00:1c.5: [ 0] Receiver Error

-[0000:00]-+-00.0 Intel Corporation Device 1904
+-02.0 Intel Corporation Device 1916
+-04.0 Intel Corporation Device 1903
+-08.0 Intel Corporation Device 1911
+-14.0 Intel Corporation Device 9d2f
+-14.2 Intel Corporation Device 9d31
+-15.0 Intel Corporation Device 9d60
+-15.1 Intel Corporation Device 9d61
+-16.0 Intel Corporation Device 9d3a
+-17.0 Intel Corporation Device 9d03
+-1c.0-[01]--
+-1c.4-[02]----00.0 Realtek Semiconductor Co., Ltd.
RTL8111/8168 PCI Express Gigabit Ethernet controller
+-1c.5-[03]----00.0 Realtek Semiconductor Co., Ltd. Device b723
+-1f.0 Intel Corporation Device 9d48
+-1f.2 Intel Corporation Device 9d21
+-1f.3 Intel Corporation Device 9d70
\-1f.4 Intel Corporation Device 9d23

Does this mean these messages are somehow related to the Realtek b723
device? That is the wifi card.
Using x86_64_defconfig there is not even any driver loaded for this
device, yet the messages appear quite a bit.
If I use a full config with all the relevant drivers including
rtlwifi, the frequency of these messages goes up a lot though.

My suspicion since this is a laptop is that something like a power
management change might be responsible if this is a regression as I have
seen messages like this pop up as a result of ASPM being enabled before.

It's likely not a regression, this is brand new hardware and this
message is seen on all kernels that we have tried (4.1, 4.2, master).
pcie_aspm=off also makes these messages go away.

Thanks
Daniel
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To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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Please read the FAQ at http://www.tux.org/lkml/

[Alexander Duyck]

Post by Daniel Drake
On Wed, Sep 2, 2015 at 7:57 PM, Alexander Duyck

Since it is correctable errors it is likely some sort of signalling issue.
Could we get the output of something like an lspci -vt? Then you would be
able to tell what the device is on the other side of the link from 00:1c.5
and then we could probably check to see if there has been any changes for
the device driver on the other end of the link.

"lspci -vt" reliably causes one occurance of the message, which is
logged by the kernel before lspci has written anything to stdout.
pcieport 0000:00:1c.5: AER: Corrected error received: id=00e5
pcieport 0000:00:1c.5: PCIe Bus Error: severity=Corrected,
type=Physical Layer, id=00e5(Receiver ID)
pcieport 0000:00:1c.5: device [8086:9d15] error status/mask=00000001/00002000
pcieport 0000:00:1c.5: [ 0] Receiver Error
-[0000:00]-+-00.0 Intel Corporation Device 1904
+-02.0 Intel Corporation Device 1916
+-04.0 Intel Corporation Device 1903
+-08.0 Intel Corporation Device 1911
+-14.0 Intel Corporation Device 9d2f
+-14.2 Intel Corporation Device 9d31
+-15.0 Intel Corporation Device 9d60
+-15.1 Intel Corporation Device 9d61
+-16.0 Intel Corporation Device 9d3a
+-17.0 Intel Corporation Device 9d03
+-1c.0-[01]--
+-1c.4-[02]----00.0 Realtek Semiconductor Co., Ltd.
RTL8111/8168 PCI Express Gigabit Ethernet controller
+-1c.5-[03]----00.0 Realtek Semiconductor Co., Ltd. Device b723
+-1f.0 Intel Corporation Device 9d48
+-1f.2 Intel Corporation Device 9d21
+-1f.3 Intel Corporation Device 9d70
\-1f.4 Intel Corporation Device 9d23
Does this mean these messages are somehow related to the Realtek b723
device? That is the wifi card.
Using x86_64_defconfig there is not even any driver loaded for this
device, yet the messages appear quite a bit.
If I use a full config with all the relevant drivers including
rtlwifi, the frequency of these messages goes up a lot though.

The correctable errors are likely a result of some sort of link error
between the root port 00:1c.5 and the wireless adapter at 3:00.0. What
is likely happening is that when the device is unused it transitions
down to a lower power link state like L0s or L1, and when it comes out
of that state it is likely triggering the PCIe error most likely as a
result of something during the PCIe link training sequence.

You might want to notify the manufacturer of the laptop as they may need
to address an issue in their hardware, firmware, or possibly add a
workaround to mask off Receiver Error reporting for their part via
either a PCIe quirk or driver fix.

Post by Daniel Drake

My suspicion since this is a laptop is that something like a power
management change might be responsible if this is a regression as I have
seen messages like this pop up as a result of ASPM being enabled before.

It's likely not a regression, this is brand new hardware and this
message is seen on all kernels that we have tried (4.1, 4.2, master).
pcie_aspm=off also makes these messages go away.

Correctable errors are considered a sign of the PCIe link health. In
theory they can be ignored since by definition they can be corrected by
the hardware. One thing you could do if you aren't using the wireless
card would be to simply switch off the correctable error reporting by
setting the mask bit for it in configuration space using setpci.

To do that what you could do is find the offset for the PCIe AER
configuration register for your port by doing a "lspci -vvv -s 0:1c.5"
and what you should get will be a dump listing the capabilities and
their current settings. In there you should find a line like:
Capabilities: [148 v1] Advanced Error Reporting

The 148 is the hex offset of the configuration space. The Correctable
Error mask is located at a hex offset of 0x14 from there. So adding the
hex values 0x148 and 0x14 gives us 0x15C. To disable reporting
correctable receiver errors you would just want to add a 1 to whatever
value you get from "setpci -s 0:1c.5 0x15C.l" and then write that value
back. So for example on my system I ended up with something like
"setpci -s 0:1c.5 0x15C.l=2001" where the output from the first command
was 2000.

- Alex


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[Daniel Drake]

Hi Alexander,

Reviving an old topic here...

We are seeing this "problem" on an increasing number of units from the
vendor, and searching around it can also be seen on Dell and HP
products. Always with the same Realtek b723 wifi device. e.g.
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1521173

The amount of error spam is problematic in that it slows down boot
really significantly, while printing lots of scary messages for the
user.
We tried doing a PCI MSI blacklist for affected laptops but we are
struggling to keep that blacklist updated with the increasing number
of affected models.

Enough hacks, I am wondering what we can do to solve this problem in
the mainline kernel...

On Thu, Sep 3, 2015 at 12:05 PM, Alexander Duyck

Post by Alexander Duyck

Post by Daniel Drake
On Wed, Sep 2, 2015 at 7:57 PM, Alexander Duyck

Since it is correctable errors it is likely some sort of signalling issue.
Could we get the output of something like an lspci -vt? Then you would be
able to tell what the device is on the other side of the link from 00:1c.5
and then we could probably check to see if there has been any changes for
the device driver on the other end of the link.

"lspci -vt" reliably causes one occurance of the message, which is
logged by the kernel before lspci has written anything to stdout.
pcieport 0000:00:1c.5: AER: Corrected error received: id=00e5
pcieport 0000:00:1c.5: PCIe Bus Error: severity=Corrected,
type=Physical Layer, id=00e5(Receiver ID)
pcieport 0000:00:1c.5: device [8086:9d15] error
status/mask=00000001/00002000
pcieport 0000:00:1c.5: [ 0] Receiver Error
-[0000:00]-+-00.0 Intel Corporation Device 1904
+-02.0 Intel Corporation Device 1916
+-04.0 Intel Corporation Device 1903
+-08.0 Intel Corporation Device 1911
+-14.0 Intel Corporation Device 9d2f
+-14.2 Intel Corporation Device 9d31
+-15.0 Intel Corporation Device 9d60
+-15.1 Intel Corporation Device 9d61
+-16.0 Intel Corporation Device 9d3a
+-17.0 Intel Corporation Device 9d03
+-1c.0-[01]--
+-1c.4-[02]----00.0 Realtek Semiconductor Co., Ltd.
RTL8111/8168 PCI Express Gigabit Ethernet controller
+-1c.5-[03]----00.0 Realtek Semiconductor Co., Ltd. Device b723
+-1f.0 Intel Corporation Device 9d48
+-1f.2 Intel Corporation Device 9d21
+-1f.3 Intel Corporation Device 9d70
\-1f.4 Intel Corporation Device 9d23
Does this mean these messages are somehow related to the Realtek b723
device? That is the wifi card.
Using x86_64_defconfig there is not even any driver loaded for this
device, yet the messages appear quite a bit.
If I use a full config with all the relevant drivers including
rtlwifi, the frequency of these messages goes up a lot though.

The correctable errors are likely a result of some sort of link error
between the root port 00:1c.5 and the wireless adapter at 3:00.0. What is
likely happening is that when the device is unused it transitions down to a
lower power link state like L0s or L1, and when it comes out of that state
it is likely triggering the PCIe error most likely as a result of something
during the PCIe link training sequence.
You might want to notify the manufacturer of the laptop as they may need to
address an issue in their hardware, firmware, or possibly add a workaround
to mask off Receiver Error reporting for their part via either a PCIe quirk
or driver fix.

Post by Daniel Drake

My suspicion since this is a laptop is that something like a power
management change might be responsible if this is a regression as I have
seen messages like this pop up as a result of ASPM being enabled before.

It's likely not a regression, this is brand new hardware and this
message is seen on all kernels that we have tried (4.1, 4.2, master).
pcie_aspm=off also makes these messages go away.

Correctable errors are considered a sign of the PCIe link health. In theory
they can be ignored since by definition they can be corrected by the
hardware. One thing you could do if you aren't using the wireless card
would be to simply switch off the correctable error reporting by setting the
mask bit for it in configuration space using setpci.
To do that what you could do is find the offset for the PCIe AER
configuration register for your port by doing a "lspci -vvv -s 0:1c.5" and
what you should get will be a dump listing the capabilities and their
Capabilities: [148 v1] Advanced Error Reporting
The 148 is the hex offset of the configuration space. The Correctable Error
mask is located at a hex offset of 0x14 from there. So adding the hex
values 0x148 and 0x14 gives us 0x15C. To disable reporting correctable
receiver errors you would just want to add a 1 to whatever value you get
from "setpci -s 0:1c.5 0x15C.l" and then write that value back. So for
example on my system I ended up with something like "setpci -s 0:1c.5
0x15C.l=2001" where the output from the first command was 2000.

I guess this is the most concrete suggestion for how to avoid the
issue - perhaps we can do that in rtl8723be driver probe. However, you
mentioned above that we should only do it if we aren't using the
wireless card. In this case we are using it... should we look for
another approach instead?

Thanks
Daniel

[Bjorn Helgaas]

Post by Daniel Drake
Hi Alexander,
Reviving an old topic here...
We are seeing this "problem" on an increasing number of units from the
vendor, and searching around it can also be seen on Dell and HP
products. Always with the same Realtek b723 wifi device. e.g.
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1521173
The amount of error spam is problematic in that it slows down boot
really significantly, while printing lots of scary messages for the
user.
We tried doing a PCI MSI blacklist for affected laptops but we are
struggling to keep that blacklist updated with the increasing number
of affected models.
Enough hacks, I am wondering what we can do to solve this problem in
the mainline kernel...

I think this is a bug in AER:
https://bugzilla.kernel.org/show_bug.cgi?id=109691

I think I understand the problem, but I haven't had time to fix it.
The bugzilla has a pointer to more details, and it would be awesome if
somebody would jump in.

Post by Daniel Drake
On Thu, Sep 3, 2015 at 12:05 PM, Alexander Duyck

Post by Alexander Duyck

Post by Daniel Drake
On Wed, Sep 2, 2015 at 7:57 PM, Alexander Duyck

Since it is correctable errors it is likely some sort of signalling issue.
Could we get the output of something like an lspci -vt? Then you would be
able to tell what the device is on the other side of the link from 00:1c.5
and then we could probably check to see if there has been any changes for
the device driver on the other end of the link.

"lspci -vt" reliably causes one occurance of the message, which is
logged by the kernel before lspci has written anything to stdout.
pcieport 0000:00:1c.5: AER: Corrected error received: id=00e5
pcieport 0000:00:1c.5: PCIe Bus Error: severity=Corrected,
type=Physical Layer, id=00e5(Receiver ID)
pcieport 0000:00:1c.5: device [8086:9d15] error
status/mask=00000001/00002000
pcieport 0000:00:1c.5: [ 0] Receiver Error
-[0000:00]-+-00.0 Intel Corporation Device 1904
+-02.0 Intel Corporation Device 1916
+-04.0 Intel Corporation Device 1903
+-08.0 Intel Corporation Device 1911
+-14.0 Intel Corporation Device 9d2f
+-14.2 Intel Corporation Device 9d31
+-15.0 Intel Corporation Device 9d60
+-15.1 Intel Corporation Device 9d61
+-16.0 Intel Corporation Device 9d3a
+-17.0 Intel Corporation Device 9d03
+-1c.0-[01]--
+-1c.4-[02]----00.0 Realtek Semiconductor Co., Ltd.
RTL8111/8168 PCI Express Gigabit Ethernet controller
+-1c.5-[03]----00.0 Realtek Semiconductor Co., Ltd. Device b723
+-1f.0 Intel Corporation Device 9d48
+-1f.2 Intel Corporation Device 9d21
+-1f.3 Intel Corporation Device 9d70
\-1f.4 Intel Corporation Device 9d23
Does this mean these messages are somehow related to the Realtek b723
device? That is the wifi card.
Using x86_64_defconfig there is not even any driver loaded for this
device, yet the messages appear quite a bit.
If I use a full config with all the relevant drivers including
rtlwifi, the frequency of these messages goes up a lot though.

The correctable errors are likely a result of some sort of link error
between the root port 00:1c.5 and the wireless adapter at 3:00.0. What is
likely happening is that when the device is unused it transitions down to a
lower power link state like L0s or L1, and when it comes out of that state
it is likely triggering the PCIe error most likely as a result of something
during the PCIe link training sequence.
You might want to notify the manufacturer of the laptop as they may need to
address an issue in their hardware, firmware, or possibly add a workaround
to mask off Receiver Error reporting for their part via either a PCIe quirk
or driver fix.

Post by Daniel Drake

My suspicion since this is a laptop is that something like a power
management change might be responsible if this is a regression as I have
seen messages like this pop up as a result of ASPM being enabled before.

It's likely not a regression, this is brand new hardware and this
message is seen on all kernels that we have tried (4.1, 4.2, master).
pcie_aspm=off also makes these messages go away.

Correctable errors are considered a sign of the PCIe link health. In theory
they can be ignored since by definition they can be corrected by the
hardware. One thing you could do if you aren't using the wireless card
would be to simply switch off the correctable error reporting by setting the
mask bit for it in configuration space using setpci.
To do that what you could do is find the offset for the PCIe AER
configuration register for your port by doing a "lspci -vvv -s 0:1c.5" and
what you should get will be a dump listing the capabilities and their
Capabilities: [148 v1] Advanced Error Reporting
The 148 is the hex offset of the configuration space. The Correctable Error
mask is located at a hex offset of 0x14 from there. So adding the hex
values 0x148 and 0x14 gives us 0x15C. To disable reporting correctable
receiver errors you would just want to add a 1 to whatever value you get
from "setpci -s 0:1c.5 0x15C.l" and then write that value back. So for
example on my system I ended up with something like "setpci -s 0:1c.5
0x15C.l=2001" where the output from the first command was 2000.

I guess this is the most concrete suggestion for how to avoid the
issue - perhaps we can do that in rtl8723be driver probe. However, you
mentioned above that we should only do it if we aren't using the
wireless card. In this case we are using it... should we look for
another approach instead?
Thanks
Daniel
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
More majordomo info at http://vger.kernel.org/majordomo-info.html

[Alexander Duyck]

Post by Daniel Drake
Hi Alexander,
Reviving an old topic here...
We are seeing this "problem" on an increasing number of units from the
vendor, and searching around it can also be seen on Dell and HP
products. Always with the same Realtek b723 wifi device. e.g.
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1521173
The amount of error spam is problematic in that it slows down boot
really significantly, while printing lots of scary messages for the
user.
We tried doing a PCI MSI blacklist for affected laptops but we are
struggling to keep that blacklist updated with the increasing number
of affected models.
Enough hacks, I am wondering what we can do to solve this problem in
the mainline kernel...
On Thu, Sep 3, 2015 at 12:05 PM, Alexander Duyck

Post by Alexander Duyck

Post by Daniel Drake
On Wed, Sep 2, 2015 at 7:57 PM, Alexander Duyck

Since it is correctable errors it is likely some sort of signalling issue.
Could we get the output of something like an lspci -vt? Then you would be
able to tell what the device is on the other side of the link from 00:1c.5
and then we could probably check to see if there has been any changes for
the device driver on the other end of the link.

"lspci -vt" reliably causes one occurance of the message, which is
logged by the kernel before lspci has written anything to stdout.
pcieport 0000:00:1c.5: AER: Corrected error received: id=00e5
pcieport 0000:00:1c.5: PCIe Bus Error: severity=Corrected,
type=Physical Layer, id=00e5(Receiver ID)
pcieport 0000:00:1c.5: device [8086:9d15] error
status/mask=00000001/00002000
pcieport 0000:00:1c.5: [ 0] Receiver Error
-[0000:00]-+-00.0 Intel Corporation Device 1904
+-02.0 Intel Corporation Device 1916
+-04.0 Intel Corporation Device 1903
+-08.0 Intel Corporation Device 1911
+-14.0 Intel Corporation Device 9d2f
+-14.2 Intel Corporation Device 9d31
+-15.0 Intel Corporation Device 9d60
+-15.1 Intel Corporation Device 9d61
+-16.0 Intel Corporation Device 9d3a
+-17.0 Intel Corporation Device 9d03
+-1c.0-[01]--
+-1c.4-[02]----00.0 Realtek Semiconductor Co., Ltd.
RTL8111/8168 PCI Express Gigabit Ethernet controller
+-1c.5-[03]----00.0 Realtek Semiconductor Co., Ltd. Device b723
+-1f.0 Intel Corporation Device 9d48
+-1f.2 Intel Corporation Device 9d21
+-1f.3 Intel Corporation Device 9d70
\-1f.4 Intel Corporation Device 9d23
Does this mean these messages are somehow related to the Realtek b723
device? That is the wifi card.
Using x86_64_defconfig there is not even any driver loaded for this
device, yet the messages appear quite a bit.
If I use a full config with all the relevant drivers including
rtlwifi, the frequency of these messages goes up a lot though.

The correctable errors are likely a result of some sort of link error
between the root port 00:1c.5 and the wireless adapter at 3:00.0. What is
likely happening is that when the device is unused it transitions down to a
lower power link state like L0s or L1, and when it comes out of that state
it is likely triggering the PCIe error most likely as a result of something
during the PCIe link training sequence.
You might want to notify the manufacturer of the laptop as they may need to
address an issue in their hardware, firmware, or possibly add a workaround
to mask off Receiver Error reporting for their part via either a PCIe quirk
or driver fix.

Post by Daniel Drake

My suspicion since this is a laptop is that something like a power
management change might be responsible if this is a regression as I have
seen messages like this pop up as a result of ASPM being enabled before.

It's likely not a regression, this is brand new hardware and this
message is seen on all kernels that we have tried (4.1, 4.2, master).
pcie_aspm=off also makes these messages go away.

Correctable errors are considered a sign of the PCIe link health. In theory
they can be ignored since by definition they can be corrected by the
hardware. One thing you could do if you aren't using the wireless card
would be to simply switch off the correctable error reporting by setting the
mask bit for it in configuration space using setpci.
To do that what you could do is find the offset for the PCIe AER
configuration register for your port by doing a "lspci -vvv -s 0:1c.5" and
what you should get will be a dump listing the capabilities and their
Capabilities: [148 v1] Advanced Error Reporting
The 148 is the hex offset of the configuration space. The Correctable Error
mask is located at a hex offset of 0x14 from there. So adding the hex
values 0x148 and 0x14 gives us 0x15C. To disable reporting correctable
receiver errors you would just want to add a 1 to whatever value you get
from "setpci -s 0:1c.5 0x15C.l" and then write that value back. So for
example on my system I ended up with something like "setpci -s 0:1c.5
0x15C.l=2001" where the output from the first command was 2000.

I guess this is the most concrete suggestion for how to avoid the
issue - perhaps we can do that in rtl8723be driver probe. However, you
mentioned above that we should only do it if we aren't using the
wireless card. In this case we are using it... should we look for
another approach instead?

I honestly don't recall the reason why I used the wording about "using
the wireless card". The only reason why I can think of is that
correctable errors are supposed to be used to determine link health,
but in this case you know there are issues since you are being spammed
about them constantly.

So if you are wanting to do this in code am I correct in assuming that
this worked to actually solve the problem for you?

The flood of correctable errors is probably a link training problem
that is being triggered by the fact that the device is running with
ASPM enabled. The best way to describe ASPM is that it is meant to
save power on the system by essentially turning off the link between
the CPU and/or chipset and the device. What can happen is that if the
wiring isn't the best quality it can sometimes fail and cause some
noise on the wire resulting in a correctable error.

What you should probably look at doing is seeing if you could add
something to drivers/pci/quirks.c for this specific device in this
specific platform with ASPM and AER enabled. Then you wouldn't see
the errors even if the driver for the device isn't loaded. If we
could get someone from RealTek involved in this it would be preferred
as they might have a better idea of what might exactly be going on so
that we could fix the root cause instead of just having to squelch the
symptom of the problem.

- Alex