On Tue, Jun 05, 2007 at 11:45:07AM +0100, Maciej W. Rozycki wrote:
> This is an optimised implementation of early printk() for the DECstation.
> After the recent conversion to a MIPS-specific generic routine using a
> character-by-character output the performance dropped significantly.
> This change reverts to the previous speed -- even at 9600 bps of the
> serial console the difference is visible with a naked eye; I presume for a
> framebuffer it is even worse (it may depend on exactly which one is used
> Additionally the change includes a fix for a problem that the old
> implementation had -- the format used would not actually limit the length
> of the string output. This new implementation uses a local buffer to deal
> with it -- even with this additional copying it is much faster than the
> generic function.
> Plus this driver is registered much earlier than the generic one,
> allowing one to see critical messages, such as one about an incorrect CPU
> setting used, that are produced beforehand. :-)
Queued up for 2.6.23, too.
> As a side note, the SYS_HAS_EARLY_PRINTK option could probably be called
> SYS_HAS_GENERIC_EARLY_PRINTK or something...
I take a patch to rename this :-)