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Re: J5000 LCD heartbeat



Hi, and thanks for your reply.

On Sunday 20 March 2005 19:40, you wrote:

> > I think I have an idea that it's related to CPU1 init, but I haven't
> > confirmed this yet - depending on your feedback to the idea below, I
> > won't bother tracing it down.
>
> Don't bother. I have that kind of message left on my j5k LCD has well,
> that's been there for ages, without problem.

Well, I'd like to see it gone myself, even though it doesn't do anything 
unpleasant. It is a little messy, at least having it mangled up with the 
Linux default text is.

If all it takes to prevent it is to make the lcd init happen slightly later in 
the boot process (ie after the chassis code was emitted), I'd have thought it 
would be an easy win.

> If you think about the firmware code that drives the display of chassis
> messages, it's firmware, changing how it works is pretty much not
> possible at that point. If you think about the PDC Chassis driver, that
> code doesn't work (read, "isn't activated") on j5k and other System Map
> firmware machines, it only works on PDC PAT machines (eg high end
> servers).

Yeah, true. So, if the PDC chassis driver isn't used on the j5k, how does the 
chassis message get sent from the kernel to the PDC?  I haven't worked that 
out yet.

> I don't think this is either useful nor desirable. We want to have the
> firmware messages going over whatever the led/lcd driver would have shown,
> and going into such a pain for a corner case doesn't really seem worth it.

At the very least, clearing the display first before the message is shown 
would have been helpful, imho.  

I'd personally like to have the firmware message displayed only for a limited 
time, though I can see a counter argument for this.  But not for having 
cleared the display first, though. (Whether this is possible depends on your 
answer as to how the PDC is told to display the message!)

> > Another idea I had was this:
> >
> > How about making the text scrollable? ie if the string is longer than
> > the viewport, scroll it along at a reasonable rate.
>
> That has been considered and eventually ruled out. Remember we're in
> kernel context, this is not meant to be eye candy etc. The pretty
> formatting you suggest should be eventually a userland task, certainly not
> a supplementary burden for the kernel.

Yep, agreed, that probably isn't a worthwhile thing to add. I was just 
thinking of other random ideas, that's all.

> > Did you have any hints you could give me as to fix my very occasional
> > heartbeat issue either?
>
> I recall that the LCD heartbeat is quite slow on my j5k as well, but
> nothing really awful, afaicr.

Well, here it's sufficiently slow to be utterly useless as a heartbeat, 
anyway. It usually flips state every 10-30 seconds, depending on how it 
feels. It certainly doesn't boot.

I realise the LCD functionality is something fairly minor, and that I'm being 
picky, but I'd be happy to invest some time to do some fine tuning.  The only 
two must-haves for me is to nail the INI CC01 message being displayed over 
the Linux kernel version display, and preferably to make my heart beat too ;)

Thanks,

David

> HTH
>
> Thibaut VARENE
> The PA/Linux Team
> http://www.pateam.org/

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