<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/drivers/pci/pcie, branch v5.17-rc4</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>Revert "PCI/portdrv: Do not setup up IRQs if there are no users"</title>
<updated>2022-02-11T20:16:11+00:00</updated>
<author>
<name>Bjorn Helgaas</name>
<email>bhelgaas@google.com</email>
</author>
<published>2022-02-07T22:33:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=075b7d363c675ef7fa03918881caeca3458e2a96'/>
<id>075b7d363c675ef7fa03918881caeca3458e2a96</id>
<content type='text'>
This reverts commit 0e8ae5a6ff5952253cd7cc0260df838ab4c21009.

0e8ae5a6ff59 ("PCI/portdrv: Do not setup up IRQs if there are no users")
reduced usage of IRQs when we don't think we need them.  But Joey, Sergiu,
and David reported choppy GUI rendering, systems that became unresponsive
every few seconds, incorrect values reported by cpufreq, and high IRQ 16
CPU usage.

Joey bisected the issues to 0e8ae5a6ff59, so revert it until we figure out
a better solution.

Link: https://lore.kernel.org/r/20220210222717.GA658201@bhelgaas
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215533
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215546
Reported-by: Joey Corleone &lt;joey.corleone@mail.ru&gt;
Reported-by: Sergiu Deitsch &lt;sergiu.deitsch@gmail.com&gt;
Reported-by: David Spencer &lt;dspencer577@gmail.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Cc: stable@vger.kernel.org	# v5.16+
Cc: Jan Kiszka &lt;jan.kiszka@siemens.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This reverts commit 0e8ae5a6ff5952253cd7cc0260df838ab4c21009.

0e8ae5a6ff59 ("PCI/portdrv: Do not setup up IRQs if there are no users")
reduced usage of IRQs when we don't think we need them.  But Joey, Sergiu,
and David reported choppy GUI rendering, systems that became unresponsive
every few seconds, incorrect values reported by cpufreq, and high IRQ 16
CPU usage.

Joey bisected the issues to 0e8ae5a6ff59, so revert it until we figure out
a better solution.

Link: https://lore.kernel.org/r/20220210222717.GA658201@bhelgaas
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215533
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215546
Reported-by: Joey Corleone &lt;joey.corleone@mail.ru&gt;
Reported-by: Sergiu Deitsch &lt;sergiu.deitsch@gmail.com&gt;
Reported-by: David Spencer &lt;dspencer577@gmail.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Cc: stable@vger.kernel.org	# v5.16+
Cc: Jan Kiszka &lt;jan.kiszka@siemens.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'pci/errors'</title>
<updated>2022-01-13T15:57:52+00:00</updated>
<author>
<name>Bjorn Helgaas</name>
<email>bhelgaas@google.com</email>
</author>
<published>2022-01-13T15:57:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=f5d3ca6fffeb71f304a7accae229c279e70b2216'/>
<id>f5d3ca6fffeb71f304a7accae229c279e70b2216</id>
<content type='text'>
- Add PCI_ERROR_RESPONSE and related definitions for signaling and checking
  for transaction errors on PCI (Naveen Naidu)

- Fabricate PCI_ERROR_RESPONSE data (~0) in config read wrappers, instead
  of in host controller drivers, when transactions fail on PCI (Naveen
  Naidu)

- Use PCI_POSSIBLE_ERROR() to check for possible failure of config reads
  (Naveen Naidu)

* pci/errors:
  PCI: xgene: Use PCI_ERROR_RESPONSE to identify config read errors
  PCI: hv: Use PCI_ERROR_RESPONSE to identify config read errors
  PCI: keystone: Use PCI_ERROR_RESPONSE to identify config read errors
  PCI: Use PCI_ERROR_RESPONSE to identify config read errors
  PCI: cpqphp: Use PCI_POSSIBLE_ERROR() to check config reads
  PCI/PME: Use PCI_POSSIBLE_ERROR() to check config reads
  PCI/DPC: Use PCI_POSSIBLE_ERROR() to check config reads
  PCI: pciehp: Use PCI_POSSIBLE_ERROR() to check config reads
  PCI: vmd: Use PCI_POSSIBLE_ERROR() to check config reads
  PCI/ERR: Use PCI_POSSIBLE_ERROR() to check config reads
  PCI: rockchip-host: Drop error data fabrication when config read fails
  PCI: rcar-host: Drop error data fabrication when config read fails
  PCI: altera: Drop error data fabrication when config read fails
  PCI: mvebu: Drop error data fabrication when config read fails
  PCI: aardvark: Drop error data fabrication when config read fails
  PCI: kirin: Drop error data fabrication when config read fails
  PCI: histb: Drop error data fabrication when config read fails
  PCI: exynos: Drop error data fabrication when config read fails
  PCI: mediatek: Drop error data fabrication when config read fails
  PCI: iproc: Drop error data fabrication when config read fails
  PCI: thunder: Drop error data fabrication when config read fails
  PCI: Drop error data fabrication when config read fails
  PCI: Use PCI_SET_ERROR_RESPONSE() for disconnected devices
  PCI: Set error response data when config read fails
  PCI: Add PCI_ERROR_RESPONSE and related definitions
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
- Add PCI_ERROR_RESPONSE and related definitions for signaling and checking
  for transaction errors on PCI (Naveen Naidu)

- Fabricate PCI_ERROR_RESPONSE data (~0) in config read wrappers, instead
  of in host controller drivers, when transactions fail on PCI (Naveen
  Naidu)

- Use PCI_POSSIBLE_ERROR() to check for possible failure of config reads
  (Naveen Naidu)

* pci/errors:
  PCI: xgene: Use PCI_ERROR_RESPONSE to identify config read errors
  PCI: hv: Use PCI_ERROR_RESPONSE to identify config read errors
  PCI: keystone: Use PCI_ERROR_RESPONSE to identify config read errors
  PCI: Use PCI_ERROR_RESPONSE to identify config read errors
  PCI: cpqphp: Use PCI_POSSIBLE_ERROR() to check config reads
  PCI/PME: Use PCI_POSSIBLE_ERROR() to check config reads
  PCI/DPC: Use PCI_POSSIBLE_ERROR() to check config reads
  PCI: pciehp: Use PCI_POSSIBLE_ERROR() to check config reads
  PCI: vmd: Use PCI_POSSIBLE_ERROR() to check config reads
  PCI/ERR: Use PCI_POSSIBLE_ERROR() to check config reads
  PCI: rockchip-host: Drop error data fabrication when config read fails
  PCI: rcar-host: Drop error data fabrication when config read fails
  PCI: altera: Drop error data fabrication when config read fails
  PCI: mvebu: Drop error data fabrication when config read fails
  PCI: aardvark: Drop error data fabrication when config read fails
  PCI: kirin: Drop error data fabrication when config read fails
  PCI: histb: Drop error data fabrication when config read fails
  PCI: exynos: Drop error data fabrication when config read fails
  PCI: mediatek: Drop error data fabrication when config read fails
  PCI: iproc: Drop error data fabrication when config read fails
  PCI: thunder: Drop error data fabrication when config read fails
  PCI: Drop error data fabrication when config read fails
  PCI: Use PCI_SET_ERROR_RESPONSE() for disconnected devices
  PCI: Set error response data when config read fails
  PCI: Add PCI_ERROR_RESPONSE and related definitions
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'pci/enumeration'</title>
<updated>2022-01-13T15:57:43+00:00</updated>
<author>
<name>Bjorn Helgaas</name>
<email>bhelgaas@google.com</email>
</author>
<published>2022-01-13T15:57:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=fb6c45130a4ad48cc7bf27399fe812379de013a8'/>
<id>fb6c45130a4ad48cc7bf27399fe812379de013a8</id>
<content type='text'>
- Use pci_find_vsec_capability() instead of open-coding it (Andy
  Shevchenko)

- Convert pci_dev_present() stub from macro to static inline to avoid
  'unused variable' errors (Hans de Goede)

- Convert sysfs slot attributes from default_attrs to default_groups (Greg
  Kroah-Hartman)

- Use DWORD accesses for LTR, L1 SS to avoid BayHub OZ711LV2 erratum (Rajat
  Jain)

- Remove unnecessary initialization of static variables (Longji Guo)

* pci/enumeration:
  x86/PCI: Remove initialization of static variables to false
  PCI: Use DWORD accesses for LTR, L1 SS to avoid erratum
  PCI/sysfs: Use default_groups in kobj_type for slot attrs
  PCI: Convert pci_dev_present() stub to static inline
  PCI: Use pci_find_vsec_capability() when looking for TBT devices
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
- Use pci_find_vsec_capability() instead of open-coding it (Andy
  Shevchenko)

- Convert pci_dev_present() stub from macro to static inline to avoid
  'unused variable' errors (Hans de Goede)

- Convert sysfs slot attributes from default_attrs to default_groups (Greg
  Kroah-Hartman)

- Use DWORD accesses for LTR, L1 SS to avoid BayHub OZ711LV2 erratum (Rajat
  Jain)

- Remove unnecessary initialization of static variables (Longji Guo)

* pci/enumeration:
  x86/PCI: Remove initialization of static variables to false
  PCI: Use DWORD accesses for LTR, L1 SS to avoid erratum
  PCI/sysfs: Use default_groups in kobj_type for slot attrs
  PCI: Convert pci_dev_present() stub to static inline
  PCI: Use pci_find_vsec_capability() when looking for TBT devices
</pre>
</div>
</content>
</entry>
<entry>
<title>PCI: Use DWORD accesses for LTR, L1 SS to avoid erratum</title>
<updated>2022-01-11T16:41:24+00:00</updated>
<author>
<name>Rajat Jain</name>
<email>rajatja@google.com</email>
</author>
<published>2021-12-22T01:21:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=4353594eb0980c80e24ebb20d9c871ff95b3b789'/>
<id>4353594eb0980c80e24ebb20d9c871ff95b3b789</id>
<content type='text'>
Some devices have an erratum such that they only support DWORD accesses to
some registers.  E.g., this Bayhub O2 device ([VID:DID] = [0x1217:0x8621])
only supports DWORD accesses to LTR latency registers and L1 PM substates
control registers:

  https://github.com/rajatxjain/public_shared/blob/main/OZ711LV2_appnote.pdf

The L1 PM substate control registers are DWORD sized, and hence their
access in the kernel is already DWORD sized, so we don't need to do
anything for them.

However, the LTR registers being WORD sized, are in need of a solution.
Convert the WORD sized accesses to these registers into DWORD sized
accesses while saving and restoring them.

Link: https://lore.kernel.org/r/20211222012105.3438916-1-rajatja@google.com
Signed-off-by: Rajat Jain &lt;rajatja@google.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Some devices have an erratum such that they only support DWORD accesses to
some registers.  E.g., this Bayhub O2 device ([VID:DID] = [0x1217:0x8621])
only supports DWORD accesses to LTR latency registers and L1 PM substates
control registers:

  https://github.com/rajatxjain/public_shared/blob/main/OZ711LV2_appnote.pdf

The L1 PM substate control registers are DWORD sized, and hence their
access in the kernel is already DWORD sized, so we don't need to do
anything for them.

However, the LTR registers being WORD sized, are in need of a solution.
Convert the WORD sized accesses to these registers into DWORD sized
accesses while saving and restoring them.

Link: https://lore.kernel.org/r/20211222012105.3438916-1-rajatja@google.com
Signed-off-by: Rajat Jain &lt;rajatja@google.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PCI/ASPM: Remove struct aspm_latency</title>
<updated>2021-11-19T22:46:26+00:00</updated>
<author>
<name>Saheed O. Bolarinwa</name>
<email>refactormyself@gmail.com</email>
</author>
<published>2021-11-19T19:37:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=fa285baf844303d119d657d4f97e0777acd51b8e'/>
<id>fa285baf844303d119d657d4f97e0777acd51b8e</id>
<content type='text'>
The struct aspm_latency is now used only inside pcie_aspm_check_latency().

Replace struct aspm_latency variables with u32 variables and remove struct
aspm_latency.

Link: https://lore.kernel.org/r/20211119193732.12343-5-refactormyself@gmail.com
Signed-off-by: Saheed O. Bolarinwa &lt;refactormyself@gmail.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The struct aspm_latency is now used only inside pcie_aspm_check_latency().

Replace struct aspm_latency variables with u32 variables and remove struct
aspm_latency.

Link: https://lore.kernel.org/r/20211119193732.12343-5-refactormyself@gmail.com
Signed-off-by: Saheed O. Bolarinwa &lt;refactormyself@gmail.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PCI/ASPM: Stop caching device L0s, L1 acceptable exit latencies</title>
<updated>2021-11-19T22:46:21+00:00</updated>
<author>
<name>Saheed O. Bolarinwa</name>
<email>refactormyself@gmail.com</email>
</author>
<published>2021-11-19T19:37:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=6e332df7c380a7bc936275cba1ed356d9eb36b39'/>
<id>6e332df7c380a7bc936275cba1ed356d9eb36b39</id>
<content type='text'>
Previously we calculated the device's acceptable L0s and L1 exit latencies
in pcie_aspm_cap_init() and cached them in struct pcie_link_state.

These values are only used in pcie_aspm_check_latency() where they are
compared with the actual exit latencies of the link.  This path is used
when removing or changing the D state of the device, so it's relatively low
frequency.

To reduce the amount of per-link data we store, remove the acceptable[]
arrays from struct pcie_link_state and calculate them directly from the
already-cached Device Capabilities register when needed.

[bhelgaas: use endpoint-&gt;devcap instead of reading it again]
Link: https://lore.kernel.org/r/20211119193732.12343-4-refactormyself@gmail.com
Signed-off-by: Saheed O. Bolarinwa &lt;refactormyself@gmail.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Previously we calculated the device's acceptable L0s and L1 exit latencies
in pcie_aspm_cap_init() and cached them in struct pcie_link_state.

These values are only used in pcie_aspm_check_latency() where they are
compared with the actual exit latencies of the link.  This path is used
when removing or changing the D state of the device, so it's relatively low
frequency.

To reduce the amount of per-link data we store, remove the acceptable[]
arrays from struct pcie_link_state and calculate them directly from the
already-cached Device Capabilities register when needed.

[bhelgaas: use endpoint-&gt;devcap instead of reading it again]
Link: https://lore.kernel.org/r/20211119193732.12343-4-refactormyself@gmail.com
Signed-off-by: Saheed O. Bolarinwa &lt;refactormyself@gmail.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PCI/ASPM: Stop caching link L0s, L1 exit latencies</title>
<updated>2021-11-19T22:46:09+00:00</updated>
<author>
<name>Saheed O. Bolarinwa</name>
<email>refactormyself@gmail.com</email>
</author>
<published>2021-11-19T19:37:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=222578dad4731cb8932471f42a0a606116ec5398'/>
<id>222578dad4731cb8932471f42a0a606116ec5398</id>
<content type='text'>
Previously we calculated the upstream and downstream L0s and L1 exit
latencies of the link in pcie_aspm_cap_init() and cached them in struct
pcie_link_state.latency_*.

These values are only used in pcie_aspm_check_latency() where they are
compared with the acceptable latencies on the link.  This path is used when
removing or changing the D state of the device, so it's relatively low
frequency.

To reduce the amount of per-link data we store, remove the latency_*
entries from struct pcie_link_state and calculate the latencies directly
where they are needed.

Link: https://lore.kernel.org/r/20211119193732.12343-3-refactormyself@gmail.com
Signed-off-by: Saheed O. Bolarinwa &lt;refactormyself@gmail.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Previously we calculated the upstream and downstream L0s and L1 exit
latencies of the link in pcie_aspm_cap_init() and cached them in struct
pcie_link_state.latency_*.

These values are only used in pcie_aspm_check_latency() where they are
compared with the acceptable latencies on the link.  This path is used when
removing or changing the D state of the device, so it's relatively low
frequency.

To reduce the amount of per-link data we store, remove the latency_*
entries from struct pcie_link_state and calculate the latencies directly
where they are needed.

Link: https://lore.kernel.org/r/20211119193732.12343-3-refactormyself@gmail.com
Signed-off-by: Saheed O. Bolarinwa &lt;refactormyself@gmail.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PCI/ASPM: Move pci_function_0() upward</title>
<updated>2021-11-19T22:15:43+00:00</updated>
<author>
<name>Bolarinwa O. Saheed</name>
<email>refactormyself@gmail.com</email>
</author>
<published>2021-11-19T19:37:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=43262f001b318a0c0531e252b47bc6b07794f356'/>
<id>43262f001b318a0c0531e252b47bc6b07794f356</id>
<content type='text'>
Move pci_function_0() earlier so we can use it from other functions.

Link: https://lore.kernel.org/r/20211119193732.12343-2-refactormyself@gmail.com
Signed-off-by: Bolarinwa O. Saheed &lt;refactormyself@gmail.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Move pci_function_0() earlier so we can use it from other functions.

Link: https://lore.kernel.org/r/20211119193732.12343-2-refactormyself@gmail.com
Signed-off-by: Bolarinwa O. Saheed &lt;refactormyself@gmail.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PCI/PME: Use PCI_POSSIBLE_ERROR() to check config reads</title>
<updated>2021-11-18T20:13:18+00:00</updated>
<author>
<name>Naveen Naidu</name>
<email>naveennaidu479@gmail.com</email>
</author>
<published>2021-11-18T14:03:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=aa66ea10ba843d35582afaadc0b2f60af063b806'/>
<id>aa66ea10ba843d35582afaadc0b2f60af063b806</id>
<content type='text'>
When config pci_ops.read() can detect failed PCI transactions, the data
returned to the CPU is PCI_ERROR_RESPONSE (~0 or 0xffffffff).

Obviously a successful PCI config read may *also* return that data if a
config register happens to contain ~0, so it doesn't definitively indicate
an error unless we know the register cannot contain ~0.

Use PCI_POSSIBLE_ERROR() to check the response we get when we read data
from hardware.  This unifies PCI error response checking and makes error
checks consistent and easier to find.

Compile tested only.

Link: https://lore.kernel.org/r/679ce049bccf10df3ca9ef4918ee2c3235afdaea.1637243717.git.naveennaidu479@gmail.com
Signed-off-by: Naveen Naidu &lt;naveennaidu479@gmail.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When config pci_ops.read() can detect failed PCI transactions, the data
returned to the CPU is PCI_ERROR_RESPONSE (~0 or 0xffffffff).

Obviously a successful PCI config read may *also* return that data if a
config register happens to contain ~0, so it doesn't definitively indicate
an error unless we know the register cannot contain ~0.

Use PCI_POSSIBLE_ERROR() to check the response we get when we read data
from hardware.  This unifies PCI error response checking and makes error
checks consistent and easier to find.

Compile tested only.

Link: https://lore.kernel.org/r/679ce049bccf10df3ca9ef4918ee2c3235afdaea.1637243717.git.naveennaidu479@gmail.com
Signed-off-by: Naveen Naidu &lt;naveennaidu479@gmail.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PCI/DPC: Use PCI_POSSIBLE_ERROR() to check config reads</title>
<updated>2021-11-18T20:13:18+00:00</updated>
<author>
<name>Naveen Naidu</name>
<email>naveennaidu479@gmail.com</email>
</author>
<published>2021-11-18T14:03:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=0242132da26a928801cbb6ab96daf77e7815e084'/>
<id>0242132da26a928801cbb6ab96daf77e7815e084</id>
<content type='text'>
When config pci_ops.read() can detect failed PCI transactions, the data
returned to the CPU is PCI_ERROR_RESPONSE (~0 or 0xffffffff).

Obviously a successful PCI config read may *also* return that data if a
config register happens to contain ~0, so it doesn't definitively indicate
an error unless we know the register cannot contain ~0.

Use PCI_POSSIBLE_ERROR() to check the response we get when we read data
from hardware.  This unifies PCI error response checking and makes error
checks consistent and easier to find.

Compile tested only.

Link: https://lore.kernel.org/r/9b0632f1f183432149f495cf12bdd5a72cc597a4.1637243717.git.naveennaidu479@gmail.com
Signed-off-by: Naveen Naidu &lt;naveennaidu479@gmail.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
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<pre>
When config pci_ops.read() can detect failed PCI transactions, the data
returned to the CPU is PCI_ERROR_RESPONSE (~0 or 0xffffffff).

Obviously a successful PCI config read may *also* return that data if a
config register happens to contain ~0, so it doesn't definitively indicate
an error unless we know the register cannot contain ~0.

Use PCI_POSSIBLE_ERROR() to check the response we get when we read data
from hardware.  This unifies PCI error response checking and makes error
checks consistent and easier to find.

Compile tested only.

Link: https://lore.kernel.org/r/9b0632f1f183432149f495cf12bdd5a72cc597a4.1637243717.git.naveennaidu479@gmail.com
Signed-off-by: Naveen Naidu &lt;naveennaidu479@gmail.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
</pre>
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