At Sun, 5 Jul 2020 21:09:27 -0700, Brian Buhrow <buhrow%nfbcal.org@localhost> wrote: Subject: Re: NetBSD-7.0 boots OK and NetBSD-8.0 hangs/crashes during boot on a MacBook7,1 > > Hello. I agree with Mouse, except that I also think it would be very > helpful and useful to have a serial console on USB only devices. Or indeed any device with any kind of USB port, e.g. a laptop. However what would be most generally useful, as opposed to ideal, would be for just the console output to appear on the first found USB serial adapter. So if the kernel can get far enough to probe a USB serial port, then it should dump the message buffer, and continue to copy everything added to the message buffer, to that USB serial device. That's the first and most important step. Make it simple, easy, and obvious how to capture all kernel messages on a modern machine without having to get all the way to the point where one can run "dmesg". Further allowing that port to be attached as the console would be "nice but not quite as necessary". Now ideally the kernel should make the best attempt to identify the first possible USB serial port as early as possible, and attach it as console, so that nothing can be missed, and so that any other bugs in device probing, etc., etc., etc., would not prevent use of DDB on this USB serial console. Even better would be to find out if the platform firmware can do some or all of this, and then to use that code both for the boot loader and the kernel console. E.g. on an EFI system, perhaps through a custom EFI driver? And for uBoot systems too? -- Greg A. Woods <gwoods%acm.org@localhost> Kelowna, BC +1 250 762-7675 RoboHack <woods%robohack.ca@localhost> Planix, Inc. <woods%planix.com@localhost> Avoncote Farms <woods%avoncote.ca@localhost>
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