On 4/18/2025 12:34 PM, Bjorn Helgaas wrote:
[+cc Kalesh, Przemek, linux-pci]
On Tue, Jan 07, 2025 at 11:01:47AM -0800, Tony Nguyen wrote:
From: En-Wei Wu <en-wei.wu@xxxxxxxxxxxxx>
When booting with a dock connected, the igc driver may get stuck for ~40
seconds if PCIe link is lost during initialization.
This happens because the driver access device after EECD register reads
return all F's, indicating failed reads. Consequently, hw->hw_addr is set
to NULL, which impacts subsequent rd32() reads. This leads to the driver
hanging in igc_get_hw_semaphore_i225(), as the invalid hw->hw_addr
prevents retrieving the expected value.
To address this, a validation check and a corresponding return value
catch is added for the EECD register read result. If all F's are
returned, indicating PCIe link loss, the driver will return -ENXIO
immediately. This avoids the 40-second hang and significantly improves
boot time when using a dock with an igc NIC.
Log before the patch:
[ 0.911913] igc 0000:70:00.0: enabling device (0000 -> 0002)
[ 0.912386] igc 0000:70:00.0: PTM enabled, 4ns granularity
[ 1.571098] igc 0000:70:00.0 (unnamed net_device) (uninitialized): PCIe link lost, device now detached
[ 43.449095] igc_get_hw_semaphore_i225: igc 0000:70:00.0 (unnamed net_device) (uninitialized): Driver can't access device - SMBI bit is set.
[ 43.449186] igc 0000:70:00.0: probe with driver igc failed with error -13
[ 46.345701] igc 0000:70:00.0: enabling device (0000 -> 0002)
[ 46.345777] igc 0000:70:00.0: PTM enabled, 4ns granularity
Log after the patch:
[ 1.031000] igc 0000:70:00.0: enabling device (0000 -> 0002)
[ 1.032097] igc 0000:70:00.0: PTM enabled, 4ns granularity
[ 1.642291] igc 0000:70:00.0 (unnamed net_device) (uninitialized): PCIe link lost, device now detached
[ 5.480490] igc 0000:70:00.0: enabling device (0000 -> 0002)
[ 5.480516] igc 0000:70:00.0: PTM enabled, 4ns granularity
Fixes: ab4056126813 ("igc: Add NVM support")
Cc: Chia-Lin Kao (AceLan) <acelan.kao@xxxxxxxxxxxxx>
Signed-off-by: En-Wei Wu <en-wei.wu@xxxxxxxxxxxxx>
Reviewed-by: Vitaly Lifshits <vitaly.lifshits@xxxxxxxxx>
Tested-by: Mor Bar-Gabay <morx.bar.gabay@xxxxxxxxx>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@xxxxxxxxx>
---
drivers/net/ethernet/intel/igc/igc_base.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/net/ethernet/intel/igc/igc_base.c b/drivers/net/ethernet/intel/igc/igc_base.c
index 9fae8bdec2a7..1613b562d17c 100644
--- a/drivers/net/ethernet/intel/igc/igc_base.c
+++ b/drivers/net/ethernet/intel/igc/igc_base.c
@@ -68,6 +68,10 @@ static s32 igc_init_nvm_params_base(struct igc_hw *hw)
u32 eecd = rd32(IGC_EECD);
u16 size;
+ /* failed to read reg and got all F's */
+ if (!(~eecd))
+ return -ENXIO;
I don't understand this. It looks like a band-aid that makes boot
faster but doesn't solve the real problem.
In its defense, I guess that with this patch, the first igc probe
fails, and then for some reason we attempt another a few seconds
later, and the second igc probe works fine, so the NIC actually does
end up working correct, right?
I think the PCI core has some issues with configuring ASPM L1.2, and I
wonder if those are relevant here. If somebody can repro the problem
(i.e., without this patch, which looks like it appeared in v6.13 as
bd2776e39c2a ("igc: return early when failing to read EECD
register")), I wonder if you could try booting with "pcie_port_pm=off
pcie_aspm.policy=performance" and see if that also avoids the problem?
If so, I'd like to see the dmesg log with "pci=earlydump" and the
"sudo lspci -vv" output when booted with and without "pcie_port_pm=off
pcie_aspm.policy=performance".
We weren't able to get a repro here.
En-Wei would you be able to provide this to Bjorn?
Thanks,
Tony
size = FIELD_GET(IGC_EECD_SIZE_EX_MASK, eecd);
/* Added to a constant, "size" becomes the left-shift value
@@ -221,6 +225,8 @@ static s32 igc_get_invariants_base(struct igc_hw *hw)
/* NVM initialization */
ret_val = igc_init_nvm_params_base(hw);
+ if (ret_val)
+ goto out;
switch (hw->mac.type) {
case igc_i225:
ret_val = igc_init_nvm_params_i225(hw);
--
2.47.1
