[PATCH 1/1] r8169: avoid unsolicited interrupts

[Aaron Ma]

From: Heiner Kallweit <hkallweit1 at gmail.com>

BugLink: https://bugs.launchpad.net/bugs/2087507

It was reported that after resume from suspend a PCI error is logged
and connectivity is broken. Error message is:
PCI error (cmd = 0x0407, status_errs = 0x0000)
The message seems to be a red herring as none of the error bits is set,
and the PCI command register value also is normal. Exception handling
for a PCI error includes a chip reset what apparently brakes connectivity
here. The interrupt status bit triggering the PCI error handling isn't
actually used on PCIe chip versions, so it's not clear why this bit is
set by the chip. Fix this by ignoring this bit on PCIe chip versions.

Fixes: 0e4851502f84 ("r8169: merge with version 8.001.00 of Realtek's r8168 driver")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219388
Tested-by: Atlas Yu <atlas.yu at canonical.com>
Signed-off-by: Heiner Kallweit <hkallweit1 at gmail.com>
Reviewed-by: Simon Horman <horms at kernel.org>
Link: https://patch.msgid.link/78e2f535-438f-4212-ad94-a77637ac6c9c@gmail.com
Signed-off-by: Paolo Abeni <pabeni at redhat.com>

(cherry picked from commit 10ce0db787004875f4dba068ea952207d1d8abeb)
Signed-off-by: Aaron Ma <aaron.ma at canonical.com>
---
 drivers/net/ethernet/realtek/r8169_main.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
index 02abe7c82ae92..ccf3b8b5db167 100644
--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c
@@ -4525,7 +4525,9 @@ static irqreturn_t rtl8169_interrupt(int irq, void *dev_instance)
 	if ((status & 0xffff) == 0xffff || !(status & tp->irq_mask))
 		return IRQ_NONE;
 
-	if (unlikely(status & SYSErr)) {
+	/* At least RTL8168fp may unexpectedly set the SYSErr bit */
+	if (unlikely(status & SYSErr &&
+	    tp->mac_version <= RTL_GIGA_MAC_VER_06)) {
 		rtl8169_pcierr_interrupt(tp->dev);
 		goto out;
 	}
-- 
2.43.0