Realtek 8111 not negotiating gigabit speeds?

[ericswpark]

Hi, I've built a new UnRAID NAS with the Asus A320I-K motherboard with the Realtek 8111 chip. Unfortunately, I can't get the Ethernet port to negotiate gigabit speeds no matter what I do – it keeps going back to 100 Mbps. My switch definitely supports Gigabit, and I've swapped several Cat5e cables to rule out a problem with the connection.

 

Output of `ethtool eth0`:

Settings for eth0:
	Supported ports: [ TP	 MII ]
	Supported link modes:   10baseT/Half 10baseT/Full
	                        100baseT/Half 100baseT/Full
	                        1000baseT/Full
	Supported pause frame use: Symmetric Receive-only
	Supports auto-negotiation: Yes
	Supported FEC modes: Not reported
	Advertised link modes:  10baseT/Half 10baseT/Full
	                        100baseT/Half 100baseT/Full
	                        1000baseT/Full
	Advertised pause frame use: Symmetric Receive-only
	Advertised auto-negotiation: Yes
	Advertised FEC modes: Not reported
	Link partner advertised link modes:  10baseT/Half 10baseT/Full
	                                     100baseT/Half 100baseT/Full
	                                     1000baseT/Full
	Link partner advertised pause frame use: Symmetric
	Link partner advertised auto-negotiation: Yes
	Link partner advertised FEC modes: Not reported
	Speed: 100Mb/s
	Duplex: Full
	Auto-negotiation: on
	master-slave cfg: preferred slave
	master-slave status: slave
	Port: Twisted Pair
	PHYAD: 0
	Transceiver: external
	MDI-X: Unknown
	Supports Wake-on: pumbg
	Wake-on: d
	Link detected: yes

 

As the report shows, UnRAID seems to know that both the link partner and the server supports gigabit speeds, but will not switch over to it for some reason.

 

Output of `lspci` (shows Realtek 8111):

00:00.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Renoir/Cezanne Root Complex
00:00.2 IOMMU: Advanced Micro Devices, Inc. [AMD] Renoir/Cezanne IOMMU
00:01.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Renoir PCIe Dummy Host Bridge
00:02.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Renoir PCIe Dummy Host Bridge
00:02.1 PCI bridge: Advanced Micro Devices, Inc. [AMD] Renoir/Cezanne PCIe GPP Bridge
00:08.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Renoir PCIe Dummy Host Bridge
00:08.1 PCI bridge: Advanced Micro Devices, Inc. [AMD] Renoir Internal PCIe GPP Bridge to Bus
00:08.2 PCI bridge: Advanced Micro Devices, Inc. [AMD] Renoir Internal PCIe GPP Bridge to Bus
00:14.0 SMBus: Advanced Micro Devices, Inc. [AMD] FCH SMBus Controller (rev 51)
00:14.3 ISA bridge: Advanced Micro Devices, Inc. [AMD] FCH LPC Bridge (rev 51)
00:18.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Renoir Device 24: Function 0
00:18.1 Host bridge: Advanced Micro Devices, Inc. [AMD] Renoir Device 24: Function 1
00:18.2 Host bridge: Advanced Micro Devices, Inc. [AMD] Renoir Device 24: Function 2
00:18.3 Host bridge: Advanced Micro Devices, Inc. [AMD] Renoir Device 24: Function 3
00:18.4 Host bridge: Advanced Micro Devices, Inc. [AMD] Renoir Device 24: Function 4
00:18.5 Host bridge: Advanced Micro Devices, Inc. [AMD] Renoir Device 24: Function 5
00:18.6 Host bridge: Advanced Micro Devices, Inc. [AMD] Renoir Device 24: Function 6
00:18.7 Host bridge: Advanced Micro Devices, Inc. [AMD] Renoir Device 24: Function 7
01:00.0 USB controller: Advanced Micro Devices, Inc. [AMD] Device 43bc (rev 02)
01:00.1 SATA controller: Advanced Micro Devices, Inc. [AMD] Device 43b8 (rev 02)
01:00.2 PCI bridge: Advanced Micro Devices, Inc. [AMD] Device 43b3 (rev 02)
02:04.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] 300 Series Chipset PCIe Port (rev 02)
02:05.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] 300 Series Chipset PCIe Port (rev 02)
02:06.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] 300 Series Chipset PCIe Port (rev 02)
02:07.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] 300 Series Chipset PCIe Port (rev 02)
05:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 15)
07:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Renoir (rev d9)
07:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Renoir Radeon High Definition Audio Controller
07:00.2 Encryption controller: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 10h-1fh) Platform Security Processor
07:00.3 USB controller: Advanced Micro Devices, Inc. [AMD] Renoir/Cezanne USB 3.1
07:00.4 USB controller: Advanced Micro Devices, Inc. [AMD] Renoir/Cezanne USB 3.1
07:00.6 Audio device: Advanced Micro Devices, Inc. [AMD] Family 17h/19h HD Audio Controller
08:00.0 SATA controller: Advanced Micro Devices, Inc. [AMD] FCH SATA Controller [AHCI mode] (rev 81)

 

I did read one report about the Realtek 8111 driver potentially being faulty and not allowing for gigabit speeds. Unfortunately, I've already built this NAS inside an ITX case and do not have a spare port to put in another Ethernet card with better compatibility. Is there some other issue at play here or would I have to wait until the drivers improve for the 8111?

[ericswpark]

EDIT: after further inspection it seems more like a cabling issue, not a driver issue. I found the following in the kernel log:

 

`dmesg | grep r8169` (r8169 is the driver used by Realtek RTL8111):

[   41.922626] Generic FE-GE Realtek PHY r8169-0-500:00: Downshift occurred from negotiated speed 1Gbps to actual speed 100Mbps, check cabling!
[   41.922658] r8169 0000:05:00.0 eth0: Link is Up - 100Mbps/Full (downshifted) - flow control rx/tx

 

Hope someone else finds this useful. As far as I can tell, the r8169 driver and RTL8111 works fine on UnRAID – if you also can't get gigabit check your kernel log and cables!