Re: [PATCH 2/2] Fix console handling during suspend/resume

Linus Torvalds
2006-06-13T23:46:44Z

On Tue, 13 Jun 2006, David Brownell wrote:
>
> Here's a related patch (well, "hack") I found helpful ... specifically to
> help let _serial_ consoles be more useful.

I just checked.

I think exactly _two_ of the six machines I have around my desk have
serial ports, and of those two, one is permanently turned off because it's
old, noisy, and just not interesting.

Maybe I'm more progressive than most, but I personally consider serial
lines pretty much dead.

> Although I must say I like Nigel's "BDI-2000 per developer" hack better.
> Even though not all boxes can hook up to a JTAG module. :(

Umm. Even more importantly, I don't think the JTAG interfaces for PC's are
necessarily even available. There is read-out logic for ARM's and embedded
PPC, but have you ever seen anything for something non-embedded?

A really useful trick the PPC people use was to put the firewire
controller into "anybody can read" mode, and use it as a kernel debugger
when it basically becomes a remote memory DMA engine. I used that to debug
some kernel hangs, and it was very nice.

However, that won't survive a power event, so it might be useful to debug
suspend problems, but generally not resume problems.

Linus