Notes for AlphaStation XP1000

• January 12, 2017
• XP1000 & Linux tulip driver, no connectivity after tulip driver loaded.
  The situation is as follows: Netbooting a kernel from the SRM and mounting the rootfs over NFS. In the SRM, ewa0 was set to 10 Mb, half duplex (i.e., mode Twisted). This enabled me to download a kernel (through bootp and tftp) and boot that kernel. Setting ewa0 to a different mode resulted in failing BOOTP requests.
  So, now the kernel is booted and the tulip driver is loaded at some point. The driver sets eth0 (i.e., ewa0 in the SRM) to 100 Mb, full duplex. A few moments later, the kernel attempts to configure eth0 by sending a BOOTP/DHCP request. Upon receiving the BOOTP/DHCP reply, the kernel should configure eth0 and be able to mount the rootfs over NFS. However, the XP1000 does not accept or receive the BOOTP/DHCP reply, so eth0 is left unconfigure and the rootfs is not mounted.
  A workaround for this problem is to force the link-partner of eth0 to 10 Mb, half duplex. But this should happen after the tulip driver has been loaded. Fortunately, the kernel tries to configure eth0 indefinitely, so when that happens you have plenty of time to set the link-partner of eth0 to the "correct" mode.
  The SRM version of this XP1000 was V5.9-1, Linux kernel 2.6.39.4.