On Mon, Aug 18, 2014 at 5:23 PM, Peter Maydell <peter.mayd...@linaro.org> wrote: > On 18 August 2014 01:14, Peter Crosthwaite <peter.crosthwa...@xilinx.com> > wrote: >> On Mon, Aug 18, 2014 at 8:23 AM, Peter Maydell <peter.mayd...@linaro.org> >> wrote: >>> On 15 August 2014 08:17, Peter Crosthwaite <peter.crosthwa...@xilinx.com> >>> wrote: >>>> If we were to repair this, a simpler and more effective check would be >>>> to only assert collisions between same-priority regions. The fact that >>>> colliding memory regions may-overlap is then left as implicit by the >>>> fact that they have different priorities. >>> >>> I'm not sure your suggestion here would work, because priorities >>> are only significant relative to other regions within the same >>> container, whereas collisions can occur between two regions >>> which don't have the same parent container and whose priorities are >>> therefore not comparable. (For instance, consider [ A [ B C ] ] >>> where A and B end up overlapping.) > >> But that is not a problem that is solved by the old may_overlap flag >> is it? The check deleted here is not hierarchy aware so we have never >> been able to detect that case. I think we should take a "clean slate" >> approach on the implementation of the collision detection. Big change >> is needed to get the check in the right place in code, whether it's >> same-priority based or using may_overlap. > > Oops, I mistakenly thought this check was happening at the > flattened-ranges point, but it's done when a subregion is > added to a container. Maybe you're right that we should be > able to allow overlaps if the priorities are different and not > otherwise, then. But I'd rather we actually did that rather than > just removing the check completely. >
Right can we call it follow up though and get a merge on this one so we can start fresh? With your new hierarchy problem we are just compounding the reasons to get rid of this code. Regards, Peter > thanks > -- PMM >
