October 17, 2008 JME 4

### NAME

jme - JMicron Technologies JMC250 Gigabit Ethernet and JMC260 Fast Ethernet controller driver

### SYNOPSIS

jme* at pci? dev ? function ?

Configuration of PHYs is necessary. See mii(4).

### DESCRIPTION

The jme device driver supports network adapters based on the JMicron Technologies JMC250 Gigabit Ethernet and JMC260 Fast Ethernet chips. The following features are supported:

  `

      IPv4 transmit/receive IP/TCP/UDP checksum offload
      IPv6 transmit TCP/UDP checksum offload
      IPv4 and IPv6 TCP segmentation offload
      VLAN tag insertion/removal
      Interrupt coalescing
      10/100/1000Mbps operation in full-duplex mode
      10/100Mbps operation in half-duplex mode
      Jumbo frames (up to 9022 bytes)

  `

Due to hardware limitation checksums and TCP segmentation offload can't be enabled if the configured MTU is larger than 4000 bytes.

Interrupt coalescing can be controlled on a per-adapter basis through the following sysctls:

hw.jme.jme<x>.int_rxtos
  jme receive interrupt moderation timer, in microseconds (defaults to 100)

hw.jme.jme<x>.int_rxct
  jme receive interrupt moderation packet counter (defaults to 128)

hw.jme.jme<x>.int_txto
  jme transmit interrupt moderation timer, in microseconds (defaults to 100)

hw.jme.jme<x>.int_txct
  jme transmit interrupt moderation packet counter (defaults to 128)

### SEE ALSO

ifmedia(4), mii(4), netintro(4), pci(4), ifconfig(8)

### HISTORY

The jme device driver first appeared in NetBSD5.0.

### BUGS

Hardware bugs prevent support of IPv6 receive TCP/UDP checksum offload in the JMC250 rev A2, and is disabled in the driver. This should be revisited when a newer hardware revision is available.