Re: [PATCH 5/9] ps3: Preallocate bootmem memory for ps3fb

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

On Tue, 2007-01-30 at 09:36 +0100, Geert Uytterhoeven wrote:
> On Tue, 30 Jan 2007, Arnd Bergmann wrote:
> > On Tuesday 30 January 2007 09:16, Geert Uytterhoeven wrote:
> > > We have a similar problem with the storage driver, which needs a block of 256
> > > KiB of contiguous memory.
> > 
> > I guess at least that one should be solveable. If the 256kb is only
> > internal flash access, it is should not be part of the storage driver
> > but of whatever else is used to drive this.
> 
> If we convert the FLASH part to a character device driver, the 256 KiB will be
> internal to the character device driver.
> 
> > Assuming the module gets loaded shortly after boot, you can still allocate
> > 256kb practically always, using get_free_pages().
> 
> I'm afraid that assumption is usually false, as you only need to access the
> FLASH when you want to change boot flags or update the boot loader.

At the same time, flash doesn't have to be fast... can't we use a
smaller bounce buffer (a page) and divide the transfer ?

Ben.