On Tue, Dec 18, 2012 at 4:00 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: > On Tuesday, December 18, 2012 03:15:12 PM Toshi Kani wrote: >> On Tue, 2012-12-18 at 22:57 +0100, Rafael J. Wysocki wrote: >> > On Tuesday, December 18, 2012 09:10:41 AM Toshi Kani wrote: >> > > On Tue, 2012-12-18 at 02:48 +0100, Rafael J. Wysocki wrote: >> : >> > > We need to decide which module is responsible for calling .bind(). I >> > > think it should be the ACPI scan module, not the ACPI PCI root bridge >> > > driver, because: >> > > - bind() needs to be called when _ADR device is added. The ACPI scan >> > > module can scan any devices, while the PCI root driver can only scan >> > > when it is added. >> > > - acpi_bus_remove() calls unbind() at hot-remove. The same module >> > > should be responsible for both bind() and unbind() handling. >> > > - It is cleaner to keep struct acpi_device_ops interface to be called >> > > by the ACPI core. >> > >> > I agree with that. :-) >> > >> > Moreover, I don't think we need acpi_pci_bind() and acpi_pci_unbind() at all. >> > >> > > So, I would propose the following changes. >> > > >> > > - Move the acpi_hot_add_bind() call back to the original place after >> > > the device_attach() call. >> > > - Rename the name of acpi_hot_add_bind() to something like >> > > acpi_bind_adr_device() since it is no longer hot-add only (and is >> > > specific to _ADR devices). >> > > - Create its pair function, acpi_unbind_adr_device(), which is called >> > > from acpi_bus_remove(). When a constructor interface is introduced, its >> > > destructor should be introduced as well. >> > > - Remove the binding procedure from acpi_pci_root_add(). This should >> > > be done in patch [2/6]. >> > >> > Well, what about moving the code from acpi_pci_bind()/acpi_pci_unbind() >> > somewhere else and removing those things altogether? >> >> Sounds nice. It will be bonus point if you can do that. :-) > > I think I can, but I need a few more patches on top of what I've already posted > to do that. > > I think that https://patchwork.kernel.org/patch/1889821/ and > https://patchwork.kernel.org/patch/1884701/ can stay as they are, since there's > some material on top of them already and I'll cut the new patches on top of all > that. I'll repost the whole series some time later this week, stay tuned. :-) I haven't follow this closely enough to give useful feedback, but I trust that what you're doing is going in the right direction. The only question I have right now is what I mentioned earlier on IRC, namely, the idea of "binding" an ACPI handle or device to a pci_dev, and whether there's a way to guarantee that the binding doesn't become stale. For example, if we bind pci_dev A to acpi_device B, I think we essentially capture the pointer to B and store that pointer in A. Obviously we want to know that the captured pointer in A remains valid as long as A exists, but I don't know what assures us of that. I don't think this is a new question; I have the same question about the current code before your changes. But it seems like you're simplifying this area in a way that might make it easier to answer the question. Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
