On Fri, Feb 23, 2024 at 1:03 AM Saravana Kannan <saravanak@xxxxxxxxxx> wrote: > > On Thu, Feb 22, 2024 at 5:34 AM Andy Shevchenko > <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote: > > > > On Wed, Feb 21, 2024 at 03:30:20PM -0800, Saravana Kannan wrote: > > > This patch series adds a "post-init-providers" device tree binding that > > > can be used to break dependency cycles in device tree and enforce a more > > > determinstic probe/suspend/resume order. This will also improve the > > > stability of global async probing and async suspend/resume and allow us > > > to enable them more easily. Yet another step away from playing initcall > > > chicken with probing and step towards fully async probing and > > > suspend/resume. > > > > Do you know what is the state of affairs in ACPI? Is there any (similar) > > issue even possible? > > I'm not very familiar with ACPI, but I wouldn't be surprised if ACPI > devices have cyclic dependencies. But then ACPI on a PC doesn't > typically have as many devices/drivers and ACPI might be hiding the > dependencies from the kernel. So maybe the possibility of a cycle > visible to the kernel might be low. > > I would really like to see fw_devlink extended to ACPI (it's written > in a way to make that possible), but don't have enough knowledge to do > it. This might happen one day, for example in the _DEP handling context (for now it is very limited, but I'm not actually sure how much more capable it needs to be). I don't think that ACPI will ever need device links between parents and children, though. On a related note, RISC-V people seem to want to use it on ACPI systems for interrupt controller dependency tracking.
