* Thierry Reding <thierry.reding@xxxxxxxxx> [131125 01:51]: > On Mon, Nov 25, 2013 at 10:25:50AM +0100, Thierry Reding wrote: > > On Sun, Nov 24, 2013 at 09:36:51PM +0000, Grant Likely wrote: > > > > > > I actually like the idea of completely allocating the resource structure > > > but leaving some entries empty. However, I agree with rmk that putting > > > garbage into a resource structure is a bad idea. What about changing the > > > value of flags to 0 or some other value to be obviously an empty > > > property and give the follow up parsing some context about which ones it > > > needs to attempt to recalculate? > > > > When I worked on this a while back I came to the same conclusion. It's > > nice to allocate all the resources at once, because the number of them > > doesn't change, only their actually values. > > I should maybe add: one issue that was raised during review of my > initial patch series was that we'll also need to cope with situations > like the following: > > 1) device's interrupt parent is probed (assigned IRQ base X) > 2) device is probed (interrupt parent there, therefore gets > assigned IRQ (X + z) > 3) device in removed > 4) device's interrupt parent is removed > 5) device is probed (deferred because interrupt parent isn't > there) > 6) device's interrupt parent is probed (assigned IRQ base Y) > 7) device is probed, gets assigned IRQ (Y + z) > > So not only do we have to track which resources are interrupt resources, > but we also need to have them reassigned everytime the device is probed, > therefore interrupt mappings need to be properly disposed and the values > invalidated when probing is deferred or the device removed. > > Having a dynamic list of properties all of a sudden doesn't sound like > such a bad idea after all. It makes handling this kind of situation > rather trivial, especially per-type lists. Those lists will be empty at > first and populated during the first probe. When probing fails or when a > device is unloaded, we dispose the mappings and empty the lists, so that > subsequent probes will start from scratch. It certainly sounds like a > bit of a waste of CPU cycles, but on the other hand it makes the code > much simpler. Looks like we cannot yet use devm_allocate, but that seems like a nice solution in the long run. I just posted an updated patch to fix the $Subject bug for the -rc cycle to this thread with more comments regarding dynamically allocating the resources. Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
