Linux-2.6.35.4 NFS 根文件系统挂不上

使用uboot的nfs命令能连上pc并下载文件。但是，内核无法挂上根文件系统。用个防火墙看了下，好像与PC机没有连接。开发板网接口那只有绿灯亮，黄灯不亮。
内核配置是使用make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi-  mini2440_defconfig 没有更改这个默认内配置。
同时我使用2.6.37内核也是有同样问题。
从输出上看认出了dm9000
求解释，或提供思路。
感激不尽。


## Booting kernel from Legacy Image at 33000000 ...                            
   Image Name:   Linux-2.6.35.4                                                
   Created:      2011-03-17  10:41:46 UTC                                      
   Image Type:   ARM Linux Kernel Image (uncompressed)                          
   Data Size:    2085552 Bytes =  2 MB                                          
   Load Address: 30008000                                                      
   Entry Point:  30008000                                                      
   Verifying Checksum ... OK                                                    
   Loading Kernel Image ... OK                                                  
OK                                                                              
                                                                                
Starting kernel ...                                                            
                                                                                
Uncompressing Linux... done, booting the kernel.                                
Linux version 2.6.35.4 (ll@ll-desktop) (gcc version 4.4.5 (GCC) ) #3 Thu Mar 171
CPU: ARM920T [41129200] revision 0 (ARMv4T), cr=c0007177                        
CPU: VIVT data cache, VIVT instruction cache                                    
Machine: MINI2440                                                              
Memory policy: ECC disabled, Data cache writeback                              
CPU S3C2440A (id 0x32440001)                                                    
S3C24XX Clocks, Copyright 2004 Simtec Electronics                              
S3C244X: core 405.000 MHz, memory 101.250 MHz, peripheral 50.625 MHz            
CLOCK: Slow mode (1.500 MHz), fast, MPLL on, UPLL on                            
Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 16256      
Kernel command line: noinitrd root=/dev/nfs rw nfsroot=192.168.9.4:/export ip=1M
PID hash table entries: 256 (order: -2, 1024 bytes)                            
Dentry cache hash table entries: 8192 (order: 3, 32768 bytes)                  
Inode-cache hash table entries: 4096 (order: 2, 16384 bytes)                    
Memory: 64MB = 64MB total                                                      
Memory: 60684k/60684k available, 4852k reserved, 0K highmem                    
Virtual kernel memory layout:                                                  
    vector  : 0xffff0000 - 0xffff1000   (   4 kB)                              
    fixmap  : 0xfff00000 - 0xfffe0000   ( 896 kB)                              
    DMA     : 0xffc00000 - 0xffe00000   (   2 MB)                              
    vmalloc : 0xc4800000 - 0xe0000000   ( 440 MB)                              
    lowmem  : 0xc0000000 - 0xc4000000   (  64 MB)                              
    modules : 0xbf000000 - 0xc0000000   (  16 MB)                              
      .init : 0xc0008000 - 0xc0029000   ( 132 kB)                              
      .text : 0xc0029000 - 0xc03b1000   (3616 kB)                              
      .data : 0xc03c8000 - 0xc03f0ee0   ( 164 kB)                              
SLUB: Genslabs=11, HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1        
Hierarchical RCU implementation.                                                
        RCU-based detection of stalled CPUs is disabled.                        
        Verbose stalled-CPUs detection is disabled.                            
NR_IRQS:85                                                                      
irq: clearing subpending status 00000003                                        
irq: clearing subpending status 00000002                                        
Console: colour dummy device 80x30                                              
console [ttySAC0] enabled                                                      
Calibrating delay loop... 201.93 BogoMIPS (lpj=504832)                          
pid_max: default: 32768 minimum: 301                                            
Mount-cache hash table entries: 512                                            
CPU: Testing write buffer coherency: ok                                        
gpiochip_add: gpios 288..303 (GPIOK) failed to register                        
gpiochip_add: gpios 320..334 (GPIOL) failed to register                        
gpiochip_add: gpios 352..353 (GPIOM) failed to register                        
NET: Registered protocol family 16                                              
MINI2440: Option string mini2440=0tb                                            
MINI2440: 't' ignored, touchscreen not compiled in                              
MINI2440: LCD [0:240x320] 1:800x480 2:1024x768                                  
S3C2440: Initialising architecture                                              
S3C2440: IRQ Support                                                            
S3C24XX DMA Driver, Copyright 2003-2006 Simtec Electronics                      
DMA channel 0 at c4808000, irq 33                                              
DMA channel 1 at c4808040, irq 34                                              
DMA channel 2 at c4808080, irq 35                                              
DMA channel 3 at c48080c0, irq 36                                              
S3C244X: Clock Support, DVS off                                                
bio: create slab <bio-0> at 0                                                  
usbcore: registered new interface driver usbfs                                  
usbcore: registered new interface driver hub                                    
usbcore: registered new device driver usb                                      
s3c-i2c s3c2440-i2c: slave address 0x10                                        
s3c-i2c s3c2440-i2c: bus frequency set to 98 KHz                                
s3c-i2c s3c2440-i2c: i2c-0: S3C I2C adapter                                    
Advanced Linux Sound Architecture Driver Version 1.0.23.                        
NET: Registered protocol family 2                                              
IP route cache hash table entries: 1024 (order: 0, 4096 bytes)                  
TCP established hash table entries: 2048 (order: 2, 16384 bytes)                
TCP bind hash table entries: 2048 (order: 1, 8192 bytes)                        
TCP: Hash tables configured (established 2048 bind 2048)                        
TCP reno registered                                                            
UDP hash table entries: 256 (order: 0, 4096 bytes)                              
UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)                        
NET: Registered protocol family 1                                              
RPC: Registered udp transport module.                                          
RPC: Registered tcp transport module.                                          
RPC: Registered tcp NFSv4.1 backchannel transport module.                      
JFFS2 version 2.2. (NAND)

RPC: Registered tcp NFSv4.1 backchannel transport module.           （这是输出继续，突然发现了这一句话。。）            
JFFS2 version 2.2. (NAND) © 2001-2006 Red Hat, Inc.                            
ROMFS MTD (C) 2007 Red Hat, Inc.                                                
msgmni has been set to 118                                                      
alg: No test for stdrng (krng)                                                  
io scheduler noop registered                                                    
io scheduler deadline registered                                                
io scheduler cfq registered (default)                                          
Console: switching to colour frame buffer device 60x53                          
fb0: s3c2410fb frame buffer device                                              
s3c2440-uart.0: s3c2410_serial0 at MMIO 0x50000000 (irq = 70) is a S3C2440      
s3c2440-uart.1: s3c2410_serial1 at MMIO 0x50004000 (irq = 73) is a S3C2440      
s3c2440-uart.2: s3c2410_serial2 at MMIO 0x50008000 (irq = 76) is a S3C2440      
brd: module loaded                                                              
at24 0-0050: 1024 byte 24c08 EEPROM (writable)                                  
S3C24XX NAND Driver, (c) 2004 Simtec Electronics                                
s3c24xx-nand s3c2440-nand: Tacls=1, 9ns Twrph0=3 29ns, Twrph1=2 19ns            
s3c24xx-nand s3c2440-nand: NAND soft ECC                                        
NAND device: Manufacturer ID: 0xec, Chip ID: 0xda (Samsung NAND 256MiB 3,3V 8-b)
Creating 4 MTD partitions on "NAND 256MiB 3,3V 8-bit":                          
0x000000000000-0x000000040000 : "u-boot"                                        
uncorrectable error :                                                          
0x000000040000-0x000000060000 : "u-boot-env"                                    
0x000000060000-0x000000560000 : "kernel"                                        
uncorrectable error :                                                          
0x000000560000-0x000010000000 : "root"                                          
uncorrectable error :                                                          
dm9000 Ethernet Driver, V1.31                                                  
eth0: dm9000e at c486e300,c4872304 IRQ 51 MAC: 08:00:3e:26:0a:5b (chip)        
ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver                          
s3c2410-ohci s3c2410-ohci: S3C24XX OHCI                                        
s3c2410-ohci s3c2410-ohci: new USB bus registered, assigned bus number 1        
s3c2410-ohci s3c2410-ohci: irq 42, io mem 0x49000000                            
hub 1-0:1.0: USB hub found                                                      
hub 1-0:1.0: 2 ports detected                                                  
usbcore: registered new interface driver libusual                              
s3c2440-usbgadget s3c2440-usbgadget: S3C2440: increasing FIFO to 128 bytes      
mice: PS/2 mouse device common for all mice                                    
input: gpio-keys as /devices/platform/gpio-keys/input/input0                    
S3C24XX RTC, (c) 2004,2006 Simtec Electronics                                  
s3c-rtc s3c2410-rtc: rtc disabled, re-enabling                                  
s3c-rtc s3c2410-rtc: rtc core: registered s3c as rtc0                          
i2c /dev entries driver                                                        
S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics                            
s3c2410-wdt s3c2410-wdt: watchdog inactive, reset disabled, irq enabled        
cpuidle: using governor ladder                                                  
sdhci: Secure Digital Host Controller Interface driver                          
sdhci: Copyright(c) Pierre Ossman                                              
s3c-sdi s3c2440-sdi: powered down.                                              
s3c-sdi s3c2440-sdi: mmc0 - using pio, sw SDIO IRQ                              
usbcore: registered new interface driver hiddev                                
usbcore: registered new interface driver usbhid                                
usbhid: USB HID core driver                                                    
No device for DAI UDA134X                                                      
No device for DAI s3c24xx-i2s                                                  
S3C24XX_UDA134X SoC Audio driver                                                
UDA134X SoC Audio Codec                                                        
asoc: UDA134X <-> s3c24xx-i2s mapping ok                                        
ALSA device list:                                                              
  #0: S3C24XX_UDA134X (UDA134X)                                                
TCP cubic registered                                                            
NET: Registered protocol family 17                                              
s3c-rtc s3c2410-rtc: setting system clock to 2005-10-25 19:33:01 UTC (113026878)
eth0: link down                                                                
IP-Config: Complete:                                                            
     device=eth0, addr=192.168.9.222, mask=255.255.255.0, gw=192.168.9.254,    
     host=192.168.9.222, domain=, nis-domain=(none),                            
     bootserver=192.168.9.4, rootserver=192.168.9.4, rootpath=                  
Looking up port of RPC 100003/2 on 192.168.9.4                                  
eth0: link up, 100Mbps, full-duplex, lpa 0x45E1                                
rpcbind: server 192.168.9.4 not responding, timed out                          
Root-NFS: Unable to get nfsd port number from server, using default            
Looking up port of RPC 100005/1 on 192.168.9.4                                  
rpcbind: server 192.168.9.4 not responding, timed out                          
Root-NFS: Unable to get mountd port number from server, using default          
Root-NFS: Server returned error -110 while mounting /export                    
VFS: Unable to mount root fs via NFS, trying floppy.                            
VFS: Cannot open root device "nfs" or unknown-block(2,0)                        
Please append a correct "root=" boot option; here are the available partitions:
1f00             256 mtdblock0 (driver?)                                        
1f01             128 mtdblock1 (driver?)                                        
1f02            5120 mtdblock2 (driver?)                                        
1f03          256640 mtdblock3 (driver?)                                        
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(2,0)  
[<c002e584>] (unwind_backtrace+0x0/0xf0) from [<c02d5988>] (panic+0x54/0xe0)    
[<c02d5988>] (panic+0x54/0xe0) from [<c0008ebc>] (mount_block_root+0x1c8/0x208)
[<c0008ebc>] (mount_block_root+0x1c8/0x208) from [<c0009150>] (prepare_namespac)
[<c0009150>] (prepare_namespace+0x160/0x1b8) from [<c0008468>] (kernel_init+0x1)
[<c0008468>] (kernel_init+0x10c/0x14c) from [<c002a82c>] (kernel_thread_exit+0x)

2.6.38也有这个问题