On Thu, Jun 28, 2012 at 10:46:58AM -0600, Stephen Warren wrote: > On 06/28/2012 12:18 AM, Hiroshi Doyu wrote: > > On Wed, 27 Jun 2012 16:44:14 +0200 > > Thierry Reding <thierry.reding@xxxxxxxxxxxxxxxxx> wrote: > > > >>> I think that "coherent_pool" can be used only when the amount of > >>> contiguous memory is short in your system. Otherwise even unnecessary. > >>> > >>> Could you explain a bit more why you want carveout size on per-board basis? > >> > >> In the ideal case I would want to not have a carveout size at all. > >> However there may be situations where you need to make sure some driver > >> can allocate a given amount of memory. Having to specify this using a > >> kernel command-line parameter is cumbersome because it may require > >> changes to the bootloader or whatever. So if you know that a particular > >> board always needs 128 MiB of carveout, then it makes sense to specify > >> it on a per-board basis. > > > > Hm...I could understand somewhat;) but DT can also specify "bootargs" > > in dts file, which can support per-board-wide spec too, like the above > > sum of carveout needed from all drivers. I just want to avoid > > introducing a new parameter additionaly if we can make use of the > > existing mechanism. > > The bootargs in the DT file is usually provided by (over-written by) the > bootloader. If we start requiring lots of random kernel command-line > arguments, that makes it more effort for the user of the bootloader > (e.g. distribution bootloader scripts, etc.) to create the kernel > command-line. I'd prefer to avoid that as much as possible. That said, > using a standardized command-line option that is (or will be) used by > all (ARM?) SoCs for the same purpose is reasonable, because there's > commonality there. I propose we stick with the default CMA settings for now and see where we end up. No need to jump the gun. Thierry
Attachment:
pgpw4zhat9Bn1.pgp
Description: PGP signature
