table of contents
JME(4) | Device Drivers Manual | JME(4) |
NAME¶
jme
—
JMicron Gigabit/Fast Ethernet driver
SYNOPSIS¶
To compile this driver into the kernel, place the following lines in your kernel configuration file:device miibus
device jme
if_jme_load="YES"
DESCRIPTION¶
Thejme
device driver provides support for
JMicron JMC25x PCI Express Gigabit Ethernet controllers and JMicron JMC26x PCI
Express Fast Ethernet controllers.
All LOMs supported by the jme
driver have
TCP/UDP/IP checksum offload for both transmit and receive, TCP segmentation
offload (TSO), hardware VLAN tag stripping/insertion features, Wake On Lan
(WOL) and an interrupt coalescing/moderation mechanism as well as a 64-bit
multicast hash filter.
The JMC25x also supports Jumbo Frames (up to 9216 bytes), which can be
configured via the interface MTU setting. Selecting an MTU larger than 1500
bytes with the ifconfig(8) utility configures the
adapter to receive and transmit Jumbo Frames.
The jme
driver supports the following media
types:
autoselect
- Enable autoselection of the media type and options. The user can manually override the autoselected mode by adding media options to rc.conf(5).
10baseT/UTP
- Set 10Mbps operation.
100baseTX
- Set 100Mbps (Fast Ethernet) operation.
1000baseTX
- Set 1000baseTX operation over twisted pair.
jme
driver supports the following media
options:
full-duplex
- Force full duplex operation.
half-duplex
- Force half duplex operation.
HARDWARE¶
Thejme
device driver provides support for
the following Ethernet controllers:
- JMicron JMC250 PCI Express Gigabit Ethernet controller
- JMicron JMC251 PCI Express Gigabit Ethernet with Card Read Host controller
- JMicron JMC260 PCI Express Fast Ethernet controller
- JMicron JMC261 PCI Express Gigabit Ethernet with Card Read Host controller
LOADER TUNABLES¶
Tunables can be set at the loader(8) prompt before booting the kernel or stored in loader.conf(5).- hw.jme.msi_disable
- This tunable disables MSI support on the Ethernet hardware. The default value is 0.
- hw.jme.msix_disable
- This tunable disables MSI-X support on the Ethernet hardware. The default value is 0.
SYSCTL VARIABLES¶
The following variables are available as both sysctl(8) variables and loader(8) tunables:- dev.jme.%d.tx_coal_to
- This variable sets the maximum amount of time to delay before sending a Tx completion interrupt, in microseconds. The accepted range is 1 to 65535; the default is 100 (100us).
- dev.jme.%d.tx_coal_pkt
- This variable sets the maximum number of outgoing packets which may be coalesced together into a single Tx completion interrupt. The accepted range is 1 to 255; the default is 8.
- dev.jme.%d.rx_coal_to
- This variable sets the maximum amount of time to wait for additional packets to arrive (for possible packet coalescing) before firing an Rx completion interrupt, in microseconds. The accepted range is 1 to 65535; the default is 100 (100us).
- dev.jme.%d.rx_coal_pkt
- This variable sets the maximum number of incoming packets which may be coalesced into a single Rx completion interrupt. The accepted range is 1 to 255; the default is 2.
- dev.jme.%d.process_limit
- This variable sets the maximum number of events that will be processed in a single batch before the handler is requeued into a taskqueue. The accepted range is 10 to 255; the default value is 128 events. The interface does not need to be brought down and up again before a change takes effect.
SEE ALSO¶
altq(4), arp(4), miibus(4), netintro(4), ng_ether(4), vlan(4), ifconfig(8)HISTORY¶
Thejme
driver was written by
Pyun YongHyeon ⟨yongari@FreeBSD.org⟩. It first appeared in FreeBSD 7.1.
CAVEATS¶
Thejme
driver tries to avoid unnecessary
station address reprogramming for controllers that use eFuse to store station
address. The number of times that eFuse can be safely reprogrammed is 16 at
most. In addition, there is no way to restore the factory default station
address once the station address has been reprogrammed via eFuse. It is highly
recommended not to reprogram the station address and it is the responsibility
of the administrator to store the original station address in a safe place
when station address is changed.
There are two known 1000baseT link establishment issues with JMC25x. If the full
mask revision number of JMC25x controller is less than or equal to 4 and the
link partner enabled the IEEE 802.3az Energy Efficient Ethernet feature, the
controller will not be able to establish a 1000baseT link. Also, if the length
of the cable is longer than 120 meters, the controller can not establish a
1000baseT link. The known workaround for these issues is to force manual link
configuration with 100baseTX instead of relying on auto-negotiation. The full
mask revision number of controller can be checked with the verbose kernel boot
option. Use the lower nibble of the chip revision number to get the full mask
revision of the controller.March 4, 2012 | Debian |