Hello, On Tuesday, June 14, 2011 10:42 PM Arnd Bergmann wrote: > On Tuesday 14 June 2011 20:58:25 Zach Pfeffer wrote: > > I've seen this split bank allocation in Qualcomm and TI SoCs, with > > Samsung, that makes 3 major SoC vendors (I would be surprised if > > Nvidia didn't also need to do this) - so I think some configurable > > method to control allocations is necessarily. The chips can't do > > decode without it (and by can't do I mean 1080P and higher decode is > > not functionally useful). Far from special, this would appear to be > > the default. > > Thanks for the insight, that's a much better argument than 'something > may need it'. Are those all chips without an IOMMU or do we also > need to solve the IOMMU case with split bank allocation? > > I think I'd still prefer to see the support for multiple regions split > out into one of the later patches, especially since that would defer > the question of how to do the initialization for this case and make > sure we first get a generic way. > > You've convinced me that we need to solve the problem of allocating > memory from a specific bank eventually, but separating it from the > one at hand (contiguous allocation) should help getting the important > groundwork in at first. > > The possible conflict that I still see with per-bank CMA regions are: > > * It completely destroys memory power management in cases where that > is based on powering down entire memory banks. I don't think that per-bank CMA regions destroys memory power management more than the global CMA pool. Please note that the contiguous buffers (or in general dma-buffers) right now are unmovable so they don't fit well into memory power management. Best regards -- Marek Szyprowski Samsung Poland R&D Center -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>