mt7621 + mt7915e wifi not working and kernel panic

Describe the bug

On OpenWRT 24.10 configured on an mt7621 SOC using mt7915e WiFi PCIe module

1. WiFi will only work on cold boot.
2. on warm boot the kernel will panic and cause a reboot and eventually will startup but the WiFi will not work generating driver errors.

The issue is caused by the mt7621 driver not waiting long enough after resetting the wifi module. The following patch fixes the issue

`Index: linux-6.6.73/drivers/pci/controller/pcie-mt7621.c

--- linux-6.6.73.orig/drivers/pci/controller/pcie-mt7621.c
+++ linux-6.6.73/drivers/pci/controller/pcie-mt7621.c
@@ -60,7 +60,7 @@
#define PCIE_PORT_LINKUP BIT(0)
#define PCIE_PORT_CNT 3

-#define INIT_PORTS_DELAY_MS 100
+#define INIT_PORTS_DELAY_MS 500
#define PERST_DELAY_MS 100

/**
@@ -319,7 +319,13 @@ static void mt7621_pcie_reset_assert(str
list_for_each_entry(port, &pcie->ports, list) {
/ PCIe RC reset assert /
mt7621_control_assert(port);

• }

• // https://github.com/openwrt/openwrt/issues/12359

• // https://github.com/openwrt/mt76/issues/644

• mdelay(PERST_DELAY_MS);

• list_for_each_entry(port, &pcie->ports, list) {
  / PCIe EP reset assert /
  mt7621_rst_gpio_pcie_assert(port);
  }`

OpenWrt version

v24.10.0-5-gef122aa73d

OpenWrt release

24.10

OpenWrt target/subtarget

mt7621

Device

mt7915e

Image kind

Official downloaded image

Steps to reproduce

No response

Actual behaviour

No response

Expected behaviour

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Additional info

No response

Diffconfig

Terms

• I am reporting an issue for OpenWrt, not an unsupported fork.

Start with drivers/pci/controller/pcie-mt7621.c in the Linux 6.6.73 source and inspect the mt7621 PCIe reset and initialization paths. Compare the proposed delay changes, then validate warm-boot behavior with the mt7915e module on an mt7621 OpenWrt 24.10 system; done means WiFi initializes without driver errors or a kernel panic.