network initialization hangs

Eric Norum eric.norum at
Tue Jul 16 14:55:23 UTC 2002

On Tuesday, July 16, 2002, at 02:03 AM, Sachin K wrote:


from past 3 days i'm experimenting with network driver and bsp settings.

i have installed pc386 BSP on RedHat Linux 7.2

i'm trying to execute ntpdemo provided in netdemos-4.5.0 .

PS: i have RealTek network card "RTL 8139 "

can anyone tell me whatz happening ??

RTEMS has no 8139 driver.

FWIW, here are some of the comments from the FreeBSD driver for this 


  * The RealTek 8139 PCI NIC redefines the meaning of 'low end.' This is
  * probably the worst PCI ethernet controller ever made, with the 
  * exception of the FEAST chip made by SMC. The 8139 supports bus-master
  * DMA, but it has a terrible interface that nullifies any performance
  * gains that bus-master DMA usually offers.
  * For transmission, the chip offers a series of four TX descriptor
  * registers. Each transmit frame must be in a contiguous buffer, aligned
  * on a longword (32-bit) boundary. This means we almost always have to
  * do mbuf copies in order to transmit a frame, except in the unlikely
  * case where a) the packet fits into a single mbuf, and b) the packet
  * is 32-bit aligned within the mbuf's data area. The presence of only
  * four descriptor registers means that we can never have more than four
  * packets queued for transmission at any one time.
  * Reception is not much better. The driver has to allocate a single 
  * buffer area (up to 64K in size) into which the chip will DMA received
  * frames. Because we don't know where within this region received 
  * will begin or end, we have no choice but to copy data from the buffer
  * area into mbufs in order to pass the packets up to the higher protocol
  * levels.
  * It's impossible given this rotten design to really achieve decent
* performance at 100Mbps, unless you happen to have a 400Mhz PII or
  * some equally overmuscled CPU to drive it.
  * On the bright side, the 8139 does have a built-in PHY, although
  * rather than using an MDIO serial interface like most other NICs, the
  * PHY registers are directly accessible through the 8139's register
  * space. The 8139 supports autonegotiation, as well as a 64-bit 
  * filter.
  * The 8129 chip is an older version of the 8139 that uses an external 
  * chip. The 8129 has a serial MDIO interface for accessing the MII where
  * the 8139 lets you directly access the on-board PHY registers. We need
  * to select which interface to use depending on the chip type.

Eric Norum <eric.norum at>
Department of Electrical Engineering
University of Saskatchewan
Saskatoon, Canada.
Phone: (306) 966-5394   FAX:   (306) 966-5407
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