From: Suneel Garapati <[email protected]>
Some AER interrupt capability registers may not be present on
non Root ports. Since there is no way to check presence of
ROOT_ERR_COMMAND and ROOT_ERR_STATUS registers. Allow AER
service only on root ports.
Otherwise AER interrupt message number is read incorrectly
causing MSIX vector registration to fail and fallback to legacy
unnecessarily.
Signed-off-by: Suneel Garapati <[email protected]>
Reviewed-by: Chandrakala Chavva <[email protected]>
Reviewed-by: Sunil Kovvuri Goutham <[email protected]>
---
drivers/pci/pcie/portdrv_core.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
index 3ee63968deaa..edc355971a32 100644
--- a/drivers/pci/pcie/portdrv_core.c
+++ b/drivers/pci/pcie/portdrv_core.c
@@ -221,7 +221,16 @@ static int get_port_device_capability(struct pci_dev *dev)
}
#ifdef CONFIG_PCIEAER
+ /*
+ * Some AER interrupt capability registers may not be present on
+ * non Root ports. Since there is no way to check presence of
+ * ROOT_ERR_COMMAND and ROOT_ERR_STATUS registers. Allow AER
+ * service only on root ports. Refer PCIe rev5.0 spec v1.0 7.8.4.
+ * Otherwise AER interrupt message number is read incorrectly
+ * causing MSIX vector registration to fail and fallback to legacy.
+ */
if (dev->aer_cap && pci_aer_available() &&
+ pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT &&
(pcie_ports_native || host->native_aer)) {
services |= PCIE_PORT_SERVICE_AER;
--
2.25.1
Please note "git log --oneline drivers/pci/pcie/portdrv_core.c" and
make your patch follow the style.
On Thu, Oct 07, 2021 at 12:44:09PM -0700, Daniel Walker wrote:
> From: Suneel Garapati <[email protected]>
>
> Some AER interrupt capability registers may not be present on
> non Root ports. Since there is no way to check presence of
> ROOT_ERR_COMMAND and ROOT_ERR_STATUS registers. Allow AER
> service only on root ports.
> Otherwise AER interrupt message number is read incorrectly
> causing MSIX vector registration to fail and fallback to legacy
> unnecessarily.
Wrap to fill 75 columns.
Add blank lines between paragraphs.
Use complete sentences ("Since there is ..." is not a sentence).
Capitalize consistently ("Root ports" vs "root ports").
Use register names I can find in the spec or with grep
("ROOT_ERR_COMMAND" and "ROOT_ERR_STATUS" do not appear in the
source).
s/MSIX/MSI-X/ to match spec usage.
Also applies to code comment below.
> Signed-off-by: Suneel Garapati <[email protected]>
Needs to include your (Daniel's) Signed-off-by; see:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?id=v5.14#n365
> Reviewed-by: Chandrakala Chavva <[email protected]>
> Reviewed-by: Sunil Kovvuri Goutham <[email protected]>
> ---
> drivers/pci/pcie/portdrv_core.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
> index 3ee63968deaa..edc355971a32 100644
> --- a/drivers/pci/pcie/portdrv_core.c
> +++ b/drivers/pci/pcie/portdrv_core.c
> @@ -221,7 +221,16 @@ static int get_port_device_capability(struct pci_dev *dev)
> }
>
> #ifdef CONFIG_PCIEAER
> + /*
> + * Some AER interrupt capability registers may not be present on
> + * non Root ports. Since there is no way to check presence of
> + * ROOT_ERR_COMMAND and ROOT_ERR_STATUS registers. Allow AER
> + * service only on root ports. Refer PCIe rev5.0 spec v1.0 7.8.4.
Sec 7.8.4 talks about Root Ports and Root Complex Event Collectors
together, so I would think you would treat them the same here.
> + * Otherwise AER interrupt message number is read incorrectly
> + * causing MSIX vector registration to fail and fallback to legacy.
> + */
> if (dev->aer_cap && pci_aer_available() &&
> + pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT &&
> (pcie_ports_native || host->native_aer)) {
> services |= PCIE_PORT_SERVICE_AER;
>
> --
> 2.25.1
>