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

Nigel Cunningham
2006-06-14T00:00:08Z

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Hi.

On Wednesday 14 June 2006 09:46, Linus Torvalds wrote:
> 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.

Usb to serial converters are not completely unheard of, though. My old
omnibook even came with one. It's the one bit I still use :)

> > 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?

Yeah. Sort of kills that idea, doesn't it?

> 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.

Since just about every problem occurs at resume time, it really does seem to
me to be the case that we have to use the rtc. Great idea, by the way.

Regards,

Nigel
--
Nigel, Michelle and Alisdair Cunningham
5 Mitchell Street
Cobden 3266
Victoria, Australia

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