On Fri, Aug 12, 2011 at 02:53:05PM +0200, Arnd Bergmann wrote: > On Friday 12 August 2011, Marek Szyprowski wrote: > > > > From: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx> > > > > Steal memory from the kernel to provide coherent DMA memory to drivers. > > This avoids the problem with multiple mappings with differing attributes > > on later CPUs. > > > > Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx> > > [m.szyprowski: rebased onto 3.1-rc1] > > Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> > > Hi Marek, > > Is this the same patch that Russell had to revert because it didn't > work on some of the older machines, in particular those using > dmabounce? > > I thought that our discussion ended with the plan to use this only > for ARMv6+ (which has a problem with double mapping) but not on ARMv5 > and below (which don't have this problem but might need dmabounce). I thought we'd decided to have a pool of available CMA memory on ARMv6K to satisfy atomic allocations, which can grow and shrink in size, rather than setting aside a fixed amount of contiguous system memory. ARMv6 and ARMv7+ could use CMA directly, and <= ARMv5 can use the existing allocation method. Has something changed? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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>