OpenWRT and Supermicro
Wow! Here's one for the record books that took a bit of research for such a simple solution.
For anyone that is installing OpenWRT on a Supermicro (or any other x86_64) platform,
So, to bury the lede: vmlinuz nomodeset
(from: https://www.kernel.org/doc/Documentation/admin-guide/kernel-parameters.txt )
A 'fallback' if the incorrect Video Mode is configured that results in a blank or black screen. This can happen if Primary Display is set to IGD (BIOS Setup / Settings: Advanced, Chipset Configuration, North Bridge, Intel IGD Configuration, Primary Display (Auto, IGD, PCIE));
- Set JPG1 Jumper to Disable VGA (this only disables the VGA Port), plut in an HDMI Cable / Monitor and everything will be displayed, allowing access to the BIOS.
...and it goes without saying to upgrade to the latest BIOS, IPMI, etc. Firmware
Notes;
It's still kind of up in the air, but... Supermicro seems to designate the Integrated Graphics Device (IGD) as the VGA Port, not the HDMI Port (Display Port is unknown). Why? Because setting the JPG1 Jumper for VGA Enable/Disable to Disable (Pins 1-2 are Enable, Pins 2-3 are Disable) results in the VGA Port not working but the HDMI Port DOES work. The BIOS is an interesting thing. If Primary Display is set to IGD (BIOS Setup / Settings: Advanced, Chipset Configuration, North Bridge, Intel IGD Configuration, Primary Display (Auto, IGD, PCIE)), one might expect output to go to the VGA port. Nope, it isn't. Lesson, do NOT conflate IGD and VGA as they are not equivalent. The hint was in the block diagram of the motherboard and involves the ASPEED IPMI / BMC AST2400 Chip. The diagram shows VGA connected to the ASPEED BMC AST 2400 chip, which in turn is shown connected to the CPU via a PCIe lane. Get it? VGA is at the end of a PCIe lane, so setting the video in the BIOS to PCIe outputs to the VGA and Display Port. Of course this begs the question about where the heck is the connector for the IGD. Apparently there isn't one, which may be involved with the implementation of the ASPEED chip OR it could be the Display Port as that wasn't tested. Although the block diagram seems to indicated that the HDMI and DP connector are equivalently connected.