freebsd-skq/share/man/man4/rl.4

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.\"	Bill Paul <wpaul@ctr.columbia.edu>. All rights reserved.
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.Dd November 4, 1998
.Dt RL 4
.Os FreeBSD
.Sh NAME
.Nm rl
.Nd
RealTek 8129/8139 fast ethernet device driver
.Sh SYNOPSIS
.Cd "device rl"
.Sh DESCRIPTION
The
.Nm
driver provides support for PCI ethernet adapters and embedded
controllers based on the RealTek 8129 and 8139 fast ethernet controller
chips.
This includes the Allied Telesyn AT2550, Genius GF100TXR,
NDC Communications NE100TX-E, OvisLink LEF-8129TX, OvisLink LEF-8139TX,
Netronix Inc. EA-1210 NetEther 10/100, KTX-9130TX 10/100 Fast Ethernet,
Encore ENL832-TX 10/100 M PCI, Longshine LCS-8038TX-R, the
SMC EZ Card 10/100 PCI 1211-TX, and various other cheap adapters.
It also supports the Accton EN1207D which has a
chip labeled MPX5030 (or MPX5038) which appears to be a RealTek workalike.
.Pp
The RealTek controllers use bus master DMA but do not use a
descriptor-based data transfer mechanism.
The receiver uses a
single fixed size ring buffer from which packets must be copied
into mbufs.
For transmission, there are only four outbound packet
address registers which require all outgoing packets to be stored
as contiguous buffers.
Furthermore, outbound packet buffers must
be longword aligned or else transmission will fail.
.Pp
The 8129 differs from the 8139 in that the 8139 has an internal
PHY which is controlled through special direct access registers
whereas the 8129 uses an external PHY via an MII bus.
The 8139
supports both 10 and 100Mbps speeds in either full or half duplex.
The 8129 can support the same speeds and modes given an appropriate
PHY chip.
.Pp
The
.Nm
driver supports the following media types:
.Pp
.Bl -tag -width xxxxxxxxxxxxxxxxxxxx
.It autoselect
Enable autoselection of the media type and options.
This is only
supported if the PHY chip attached to the RealTek controller
supports NWAY autonegotiation.
The user can manually override
the autoselected mode by adding media options to the
.Pa /etc/rc.conf
file.
.It 10baseT/UTP
Set 10Mbps operation.
The
.Ar mediaopt
option can also be used to select either
.Ar full-duplex
or
.Ar half-duplex
modes.
.It 100baseTX
Set 100Mbps (fast ethernet) operation.
The
.Ar mediaopt
option can also be used to select either
.Ar full-duplex
or
.Ar half-duplex
modes.
.El
.Pp
The
.Nm
driver supports the following media options:
.Pp
.Bl -tag -width xxxxxxxxxxxxxxxxxxxx
.It full-duplex
Force full duplex operation
.It half-duplex
Force half duplex operation.
.El
.Pp
Note that the 100baseTX media type is only available if supported
by the adapter.
For more information on configuring this device, see
.Xr ifconfig 8 .
.Sh DIAGNOSTICS
.Bl -diag
.It "rl%d: couldn't map memory"
A fatal initialization error has occurred.
.It "rl%d: couldn't map interrupt"
A fatal initialization error has occurred.
.It "rl%d: watchdog timeout"
The device has stopped responding to the network, or there is a problem with
the network connection (cable).
.It "rl%d: no memory for rx list"
The driver failed to allocate an mbuf for the receiver ring.
.It "rl%d: no memory for tx list"
The driver failed to allocate an mbuf for the transmitter ring when
allocating a pad buffer or collapsing an mbuf chain into a cluster.
.It "rl%d: chip is in D3 power state -- setting to D0"
This message applies only to adapters which support power
management.
Some operating systems place the controller in low power
mode when shutting down, and some PCI BIOSes fail to bring the chip
out of this state before configuring it.
The controller loses all of
its PCI configuration in the D3 state, so if the BIOS does not set
it back to full power mode in time, it won't be able to configure it
correctly.
The driver tries to detect this condition and bring
the adapter back to the D0 (full power) state, but this may not be
enough to return the driver to a fully operational condition.
If
you see this message at boot time and the driver fails to attach
the device as a network interface, you will have to perform second
warm boot to have the device properly configured.
.Pp
Note that this condition only occurs when warm booting from another
operating system.
If you power down your system prior to booting
.Fx ,
the card should be configured correctly.
.El
.Sh SEE ALSO
.Xr arp 4 ,
.Xr netintro 4 , 
.Xr ng_ether 4 ,
.Xr ifconfig 8
.Rs
.%B The RealTek 8129 and 8139 datasheets
.%O ftp.realtek.com.tw:/lancard/data sheet
.Re
.Sh HISTORY
The
.Nm
device driver first appeared in
.Fx 3.0 .
.Sh AUTHORS
The
.Nm
driver was written by
.An Bill Paul Aq wpaul@ctr.columbia.edu .
.Sh BUGS
Since outbound packets must be longword aligned, the transmit
routine has to copy an unaligned packet into an mbuf cluster buffer
before transmission.
The driver abuses the fact that the cluster buffer
pool is allocated at system startup time in a contiguous region starting
at a page boundary.
Since cluster buffers are 2048 bytes, they are
longword aligned by definition.
The driver probably should not be
depending on this characteristic.
.Pp
The RealTek data sheets are of especially poor quality: the grammar
and spelling are awful and there is a lot of information missing,
particularly concerning the receiver operation.
One particularly
important fact that the data sheets fail to mention relates to the
way in which the chip fills in the receive buffer.
When an interrupt
is posted to signal that a frame has been received, it is possible that
another frame might be in the process of being copied into the receive
buffer while the driver is busy handling the first one.
If the driver
manages to finish processing the first frame before the chip is done
DMAing the rest of the next frame, the driver may attempt to process
the next frame in the buffer before the chip has had a chance to finish
DMAing all of it.
.Pp
The driver can check for an incomplete frame by inspecting the frame
length in the header preceding the actual packet data: an incomplete
frame will have the magic length of 0xFFF0.
When the driver encounters
this value, it knows that it has finished processing all currently
available packets.
Neither this magic value nor its significance are 
documented anywhere in the RealTek data sheets.