Re: [PATCH 02/11] PCI: rcar-gen4: Drop the APP-based link_up check
flat view
From: sashiko-bot@kernel.org
Date: 2026-09-18 03:25:03
Also in:
linux-pci
rcar_gen4_pcie_link_up() checks link state using SMLH_LINK_UP and
RDLH_LINK_UP in PCIEINTSTS0. However, these bits do not reflect the live
link state. On an R-Car S4, after taking down the endpoint, a link-down
interrupt saw PCIEINTSTS0 = 0x20a000c5 with both bits still set. Even
after resetting the controller with the LTSSM back in Polling, they read
0xa000c5, still set.
As a result, dw_pcie_link_up() keeps reporting the link as up after it
has gone down. That defeats the check in dw_pcie_other_conf_map_bus(),
which is supposed to stop config accesses to downstream devices while
the link is down, so such accesses go out on the dead link and stall the
host. It also makes the callback useless for the link-down recovery
added later, which has to wait for the link to actually come back after
resetting the controller.
Drop the callback and let the DesignWare core use its PORT_DEBUG1 check
instead, which correctly detects the downed link.
Fixes: 0d0c551011df ("PCI: rcar-gen4: Add R-Car Gen4 PCIe controller support for host mode")
Signed-off-by: Koichiro Den <redacted>Sashiko has reviewed this patch and found no issues. It looks great! -- Sashiko AI review · https://sashiko.dev/#/patchset/20260918032038.2216471-1-den@valinux.co.jp?part=2