Re: rge(4) RTL8126 simple testing

Reply: Sean C. Farley: "Re: rge(4) RTL8126 simple testing"
In reply to: Sean C. Farley: "Re: rge(4) RTL8126 simple testing"
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From: Kevin Lo <kevlo_at_kevlo.org>
Date: Fri, 27 Mar 2026 01:17:59 UTC
On Wed, Mar 04, 2026 at 04:02:37PM -0500, Sean C. Farley wrote:
> 
> On Sat, 28 Feb 2026, Sean C. Farley wrote:
> 
> > I recently upgraded my home network using a few BrosTrend 5Gb cards
> > (RTL8126) with 14-STABLE (1eb2beb3686c) and the latest commit (3170b35)
> > to the GitHub repo for if_rge.  It was either these cards or a couple of
> > Intel X550-T2 cards, but less power and less heat were the deciding
> > factors.
> > 
> > For the most part, they seem to work very well, except that they cannot
> > negotiate a 2500Base-T connection.  They can negotiate 1000baseT and
> > 5000Base-T.  This was with two different cards connecting to two
> > different devices.  If manually set, they will try for awhile than
> > fall-back to 1000baseT.
> > 
> > One other oddity is that rge0 has "ClockPM disabled", but I have not
> > looked into that.
> > 
> > The networking hardware:
> > - 3 BrosTrend 5Gb NIC's[1]  (5Gb)
> > - Zyxel NWA130BE[2]  (2.5Gb port)
> > - TRENDnet TEG-S591[3]  (connected the NIC to its 10Gb port)
> > - Nokia ONT XS-010X-Q[4]  (10Gb port)
> > 
> > ifconfig:
> > rge0: flags=1008843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,LOWER_UP>
> > metric 0 mtu 1500
> > 	options=9b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM>
> > 	capabilities=9b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM>
> >        media: Ethernet autoselect (5000Base-T <full-duplex>)
> > 	status: active
> > 	supported media:
> > 		media autoselect
> > 		media 5000Base-T mediaopt full-duplex
> > 		media 5000Base-T
> > 		media 2500Base-T mediaopt full-duplex
> > 		media 2500Base-T
> > 		media 1000baseT mediaopt full-duplex
> > 		media 1000baseT
> > 		media 100baseTX mediaopt full-duplex
> > 		media 100baseTX
> > 		media 10baseT/UTP mediaopt full-duplex
> > 		media 10baseT/UTP
> > 	nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
> > 	drivername: rge0
> > rge1:
> > flags=1008943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST,LOWER_UP>
> > metric 0 mtu 1500
> > 	options=9b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM>
> > 	capabilities=9b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM>
> > 	media: Ethernet autoselect (5000Base-T <full-duplex>)
> > 	status: active
> > 	supported media:
> > 		media autoselect
> > 		media 5000Base-T mediaopt full-duplex
> > 		media 5000Base-T
> > 		media 2500Base-T mediaopt full-duplex
> > 		media 2500Base-T
> > 		media 1000baseT mediaopt full-duplex
> > 		media 1000baseT
> > 		media 100baseTX mediaopt full-duplex
> > 		media 100baseTX
> > 		media 10baseT/UTP mediaopt full-duplex
> > 		media 10baseT/UTP
> > 	nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
> > 	drivername: rge1
> > rge2:
> > flags=1008943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST,LOWER_UP>
> > metric 0 mtu 1500
> > 	options=9b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM>
> > 	capabilities=9b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM>
> > 	media: Ethernet Other (1000baseT <full-duplex>)
> > 	status: active
> > 	supported media:
> > 		media autoselect
> > 		media 5000Base-T mediaopt full-duplex
> > 		media 5000Base-T
> > 		media 2500Base-T mediaopt full-duplex
> > 		media 2500Base-T
> > 		media 1000baseT mediaopt full-duplex
> > 		media 1000baseT
> > 		media 100baseTX mediaopt full-duplex
> > 		media 100baseTX
> > 		media 10baseT/UTP mediaopt full-duplex
> > 		media 10baseT/UTP
> > 	nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
> > 	drivername: rge2
> > 
> > pciconf:
> > rge0@pci0:1:0:0:	class=0x020000 rev=0x01 hdr=0x00 vendor=0x10ec
> > device=0x8126 subvendor=0x10ec subdevice=0x0123
> >    vendor     = 'Realtek Semiconductor Co., Ltd.'
> >    device     = 'RTL8126 5GbE Controller'
> >    class      = network
> >    subclass   = ethernet
> >    bar   [10] = type I/O Port, range 32, base 0xe000, size 256, enabled
> >    bar   [18] = type Memory, range 64, base 0xf7600000, size 65536, enabled
> >    bar   [20] = type Memory, range 64, base 0xf7610000, size 16384, enabled
> >    cap 01[40] = powerspec 3  supports D0 D1 D2 D3  current D0
> >    cap 05[50] = MSI supports 1 message, 64 bit, vector masks enabled
> > with 1 message
> >    cap 10[70] = PCI-Express 2 endpoint MSI 1 max data 256(512) RO
> >                 max read 512
> >                 link x1(x1) speed 8.0(8.0) ASPM disabled(L0s/L1) ClockPM
> > disabled
> >    cap 11[b0] = MSI-X supports 32 messages
> >                 Table in map 0x20[0x0], PBA in map 0x20[0x800]
> >    cap 03[d0] = VPD
> >    ecap 0001[100] = AER 2 0 fatal 0 non-fatal 1 corrected
> >    ecap 0002[148] = VC 1 max VC0
> >    ecap 0003[170] = Serial 1 01000000684ce000
> >    ecap 0019[180] = PCIe Sec 1 lane errors 0
> >    ecap 0017[190] = TPH Requester 1
> >    ecap 0018[21c] = LTR 1
> >    ecap 001e[224] = L1 PM Substates 1
> >    ecap 000b[234] = Vendor [1] ID 0002 Rev 4 Length 256
> > rge1@pci0:4:0:0:	class=0x020000 rev=0x01 hdr=0x00 vendor=0x10ec
> > device=0x8126 subvendor=0x10ec subdevice=0x0123
> >    vendor     = 'Realtek Semiconductor Co., Ltd.'
> >    device     = 'RTL8126 5GbE Controller'
> >    class      = network
> >    subclass   = ethernet
> >    bar   [10] = type I/O Port, range 32, base 0xd000, size 256, enabled
> >    bar   [18] = type Memory, range 64, base 0xf7500000, size 65536, enabled
> >    bar   [20] = type Memory, range 64, base 0xf7510000, size 16384, enabled
> >    cap 01[40] = powerspec 3  supports D0 D1 D2 D3  current D0
> >    cap 05[50] = MSI supports 1 message, 64 bit, vector masks enabled
> > with 1 message
> >    cap 10[70] = PCI-Express 2 endpoint MSI 1 max data 256(512) RO
> >                 max read 512
> >                 link x1(x1) speed 8.0(8.0) ASPM disabled(L0s/L1) ClockPM
> > enabled
> >    cap 11[b0] = MSI-X supports 32 messages
> >                 Table in map 0x20[0x0], PBA in map 0x20[0x800]
> >    cap 03[d0] = VPD
> >    ecap 0001[100] = AER 2 0 fatal 0 non-fatal 0 corrected
> >    ecap 0002[148] = VC 1 max VC0
> >    ecap 0003[170] = Serial 1 01000000684ce000
> >    ecap 0019[180] = PCIe Sec 1 lane errors 0
> >    ecap 0017[190] = TPH Requester 1
> >    ecap 0018[21c] = LTR 1
> >    ecap 001e[224] = L1 PM Substates 1
> >    ecap 000b[234] = Vendor [1] ID 0002 Rev 4 Length 256
> > rge2@pci0:5:0:0:	class=0x020000 rev=0x01 hdr=0x00 vendor=0x10ec
> > device=0x8126 subvendor=0x10ec subdevice=0x0123
> >    vendor     = 'Realtek Semiconductor Co., Ltd.'
> >    device     = 'RTL8126 5GbE Controller'
> >    class      = network
> >    subclass   = ethernet
> >    bar   [10] = type I/O Port, range 32, base 0xc000, size 256, enabled
> >    bar   [18] = type Memory, range 64, base 0xf7400000, size 65536, enabled
> >    bar   [20] = type Memory, range 64, base 0xf7410000, size 16384, enabled
> >    cap 01[40] = powerspec 3  supports D0 D1 D2 D3  current D0
> >    cap 05[50] = MSI supports 1 message, 64 bit, vector masks enabled
> > with 1 message
> >    cap 10[70] = PCI-Express 2 endpoint MSI 1 max data 256(512) RO
> >                 max read 512
> >                 link x1(x1) speed 8.0(8.0) ASPM disabled(L0s/L1) ClockPM
> > enabled
> >    cap 11[b0] = MSI-X supports 32 messages
> >                 Table in map 0x20[0x0], PBA in map 0x20[0x800]
> >    cap 03[d0] = VPD
> >    ecap 0001[100] = AER 2 0 fatal 0 non-fatal 0 corrected
> >    ecap 0002[148] = VC 1 max VC0
> >    ecap 0003[170] = Serial 1 01000000684ce000
> >    ecap 0019[180] = PCIe Sec 1 lane errors 0
> >    ecap 0017[190] = TPH Requester 1
> >    ecap 0018[21c] = LTR 1
> >    ecap 001e[224] = L1 PM Substates 1
> >    ecap 000b[234] = Vendor [1] ID 0002 Rev 4 Length 256
> > 
> > Sean
> >  1. https://www.brostrend.com/products/p2
> >  2. https://www.zyxel.com/us/en-us/products/wireless/be11000-6-stream-wifi-7-triple-radio-nebulaflex-access-point-nwa130be
> >  3. https://www.trendnet.com/products/2_5g-10g-switches/9-port-multi-gig-switch-TEG-S591-v1
> >  4. https://www.nokia.com/asset/210704/
> 
> I have spent awhile trying different things yet cannot get these to work at
> 2.5G.  The Realtek vendor driver cannot negotiate at 2.5G nor can Linux 6.18
> (Arch Linux).
> 
> Important details:
> - FreeBSD dmesg chip rev: RTL8126_2 (0x64a00000)

Since all the RTL8126 chip revisions I have on hand are RTL8126_1 (0x64900000), I went ahead and bought the BrosTrend 5G network card you recommended.
Purchasing directly from the BrosTrend official website wasn't an option 
since they don't ship to Taiwan, so I ordered from Amazon [1] instead.
Unfortunately, the one I received turned out to be RTL8126_1 as well. :(

[1] https://www.amazon.com/dp/B0CYZ9M3LR