Re: [PATCH] Update udbg_progress() to display the integer

[Michael Ellerman <michael@ellerman.id.au>]

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On Wed, 2007-02-07 at 10:28 -0600, Timur Tabi wrote:
> Mike Strosaker wrote:
> 
> > The op panel on recent systems has 2 lines; the first can display 16 
> > characters, the second, 80.  The first line is usually used to display 
> > an 8 character hexadecimal progress/error message (called an SRC: System 
> > Reference Code), and the second line is used to display a location code 
> > when appropriate (e.g. when the SRC indicates a device failure).  IBM 
> > documents many of their OF and RTAS SRCs deep in the Hardware 
> > Information Center:
> 
> In that case, the big question is: does the kernel conform to this standard? 
> Looking at the current usage of ppc_md.progress(), I can't help but think that 
> it being called the same way printk() is being called, i.e. at the whim of the 
> developer who wrote the code.
> 
> So let's say that we need to keep ppc_md.progress().  I think we should have 
> some way of restricting its usage to systems where it does something different 
> than printk().  On an Freescale 83xx reference board, for example, its output 
> goes to the same place as printk(), so it doesn't serve any purpose.
> 
> Perhaps we should define ppc_md.progress() such that it never sends the output 
> to the same place as printk().  If the only output device is the serial port, 
> and printk() already outputs there, then ppc_md.progress() should do nothing. 
> This would eliminate any "accidental" use of ppc_md.progress(), when printk() is 
> the better choice.

But then you'll end up with code that does:

 printk("Setup done");
 ppc_md.progress("Setup done");

Because on systems where the output _does_ go to two places, you'll want
the messages to appear in both.

I don't see what the problem is with progress messages going to the
printk buffer?

cheers

-- 
Michael Ellerman
OzLabs, IBM Australia Development Lab

wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)

We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person

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