On Thu, Mar 04, 2021 at 03:05:32PM +0100, Nicolas Saenz Julienne wrote: > Hi Greg. > > On Thu, 2021-03-04 at 14:46 +0100, Greg KH wrote: > > On Wed, Mar 03, 2021 at 03:33:12PM +0800, Jing Xiangfeng wrote: > > > Using two distinct DMA zones turned out to be problematic. Here's an > > > attempt go back to a saner default. > > > > What problem does this solve? How does this fit into the stable kernel > > rules? > > We changed the way we setup memory zones in arm64 in order to cater for > Raspberry Pi 4's weird DMA constraints: ZONE_DMA spans the lower 1GB of memory > and ZONE_DMA32 the rest of the 32bit address space. Since you can't allocate > memory that crosses zone boundaries, this broke crashkernel allocations on big > machines. This series fixes all this by parsing the HW description and checking > for DMA constrained buses. When not found, the unnecessary zone creation is > skipped. What kernel/commit caused this "breakage"? thanks, greg k-h
