Testing Notes¶
In a BIOS (not UEFI) virtual machine with both a framebuffer (VGA) and serial console (COM1/ttya), I performed the following sequence of boots with this change installed:
- booting with
console=ttya and diag-device unset
- booting with
console=text and diag-device unset
In both cases, the loader and the subsequent OS console appeared only on the nominated device, and no interaction was possible on the other device.
- booting with
console=text, and at the ok prompt, entered set diag-device=ttya and then boot
The SunOS banner, and an early notice (NOTICE: driver uhci disabled) appeared on both the framebuffer and COM1. Subsequent output from startup scripts and the login prompt appeared only on the VGA console as expected.
- booting with
console=text, and at the ok prompt, entered boot -kd
- booting with
console=ttya, and at the ok prompt, entered boot -kd
The debugger appeared only on the appropriate interface, and worked as well it usually does.
- booting with
console=text, and at the ok prompt, entered @set diag-device=ttya and then boot -kd
The debugger appeared mirrored on both consoles, and I was able to use ::bp newproc to catch some early function calls from both consoles. At some point early in boot, this log message was emitted after which the debugger was only useable on the framebuffer:
NOTICE: Kernel debugger present: disabling console power management.
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