2024-02-21 11:35:03

by Bean Huo

[permalink] [raw]
Subject: [PATCH v3] PCI: Increase maximum PCIe physical function number to 7 for non-ARI devices

From: Bean Huo <[email protected]>

As per PCIe r6.2, sec 6.13 titled "Alternative Routing-ID Interpretation
(ARI)", up to 8 [fn # 0..7] Physical Functions(PFs) are allowed in an
non-ARI capable device. Previously, our implementation erroneously limited
the maximum number of PFs to 7 for endpoints without ARI support.

This patch corrects the maximum PF count to adhere to the PCIe specification
by allowing up to 8 PFs on non-ARI capable devices. This change ensures better
compliance with the standard and improves compatibility with devices relying
on this specification.

Fixes: c3df83e01a96 ("PCI: Clean up pci_scan_slot()")
Cc: [email protected]
Signed-off-by: Bean Huo <[email protected]>
---
Changelog:
v2--v3:
1. Update commit messag
v1--v2:
1. Add Fixes tag
2. Modify commit message
---
drivers/pci/probe.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index ed6b7f48736a..8c3d0f63bc13 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2630,7 +2630,8 @@ static int next_fn(struct pci_bus *bus, struct pci_dev *dev, int fn)
if (pci_ari_enabled(bus))
return next_ari_fn(bus, dev, fn);

- if (fn >= 7)
+ /* If EP does not support ARI, the maximum number of functions should be 7 */
+ if (fn > 7)
return -ENODEV;
/* only multifunction devices may have more functions */
if (dev && !dev->multifunction)
--
2.34.1