[U-Boot-Users] logbuffer

[Frank]

--- "Michael R. Hines" <mhines at google.com> wrote:

> 
> That's what my first attempt tried to do, but it didn't seem
> to work.
> 
> I reduced mem_size (I think) inside the bd_info struct by 16K.
> 
> Just curious if there was a more properly intended way of
> going about it...
> 
> - Michael
> 
> Frank wrote:
> > --- "Michael R. Hines" <mhines at google.com> wrote:
> >
> >   
> >> I'd like to use the logbuffer functionality in u-boot...
> >>
> >> After #define'ing CONFIG_LOGBUFFER, I can
> >> successfully see our data getting printed to the reserved
> >> 16K region in dram. However, we want to grab that data
> >> back out after linux has booted.
> >>
> >> During the various initializations that linux does on boot,
> >> (somewhere before init is actually run, I believe), the
> data
> >> in the 16K buffer at the end of dram gets over-written
> >> by somebody inside linux, and is lost.
> >>
> >> I found a thread somewhere on the net where Wolfgang
> >> mentioned that linux needed a patch to be told not to
> >> intrude on those logbuffer pages, but nothing more than
> >> that.
> >>
> >> Is there a proper way to handle this?
> >>
> >> Thanks,
> >> - Michael R. Hines
> >>     
> >
> > I've never used the log buffer before, but I would think you
> > could just tell the kernel you have less memory then is
> > physically there. That way the kernel wouldn't touch the
> area
> > used by the log buffer...

Try reducing it on the kernel cmdline (mem=xxM) by 1Meg increments.

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