Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: RFC: Put printk buffer in video ram | Date | Mon, 23 Nov 2009 20:03:31 +0100 |
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On Monday 23 November 2009, Chris Friesen wrote: > We've had a mechanism sort of like this for quite a while. Hasn't been > pushed to mainline because it used board-specific hardware and we're > usually multiple kernel versions behind mainline. > > Anyways, a couple things that we've found to be useful are: > 1) The ability to allocate a chunk of this persistent memory area for a > special purpose. This allows things like memory-mapped circular buffers > for per-cpu binary data. > 2) An API to log just to this persistent area and bypass the normal > console completely. This can be useful when debugging issues where the > normal logging paths result in a hang.
Some powerpc machines have a memory-mapped nvram, in which the kernel can install persistant 'partitions'. Not all of them are memory mapped, but for those that are (e.g. IBM QS22), your approach sounds perfect.
Arnd <><
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