On Wed, 2006-04-19 at 10:28 -0700, Patrick Mochel wrote: > On Wed, Apr 19, 2006 at 10:08:57AM -0700, Kristen Accardi wrote: > > On Tue, 2006-04-18 at 15:54 -0700, Patrick Mochel wrote: > > > > > +acpi_status > > > > +register_hotplug_dock_device(acpi_handle handle, acpi_notify_handler handler, > > > > + void *context) > > > > > > If this is called from outside drivers/acpi/, you should return an int with a > > > real errno value. The AE_* values shouldn't be used outside of the ACPI CA. > > > > > > > Really? We use these all over the place in drivers/pci/hotplug. In > > fact, you kinda have to use them if you are calling certain acpi > > symbols, since they return these types. > > > > For example, here are some functions will return acpi_status that we use > > in hotplug land. > > > > pci_osc_control_set() > > acpi_run_oshp() > > acpi_walk_namespace requires its use. > > Well, it's one thing to use a function that returns a non-standard error-value, > but it's another to add more functions that do. :-) > > > I felt that by returning acpi_status I was being consistent with how > > other acpi calls acted. Is this another example of the iceberg that Len > > was talking about in a previous email?? (ugh.) > > I believe so. > > We have a standard, well-defined error namespace that lives in include/*/errno.h. > ACPI defines its own error namespace because it must be portable, and even though > most OSes will define the standard errno values, some do not, so it cannot > assume that it will be there. I'm not sure why the choice was to redefine similar > error values instead of reusing the errno values, but that's moot at this point.. > > The only place where the ACPI error values need to be used is in the ACPI CA. The > functions exposed to the OS from the CA will return AE_* because the same source > runs everywhere. However, Linux-specific code doesn't need to do that. It is free > to use Linux-specific error reporting (except in the OSL layer that the CA uses, > because it is expecting well-defined return values, as specified in the CA > Programmers Reference). > > My standpoint is that Linux-specific code should not be using any ACPI CAisms at > all because since the code is Linux-specific, it doesn't need to be portable in > the same manner that the CA is. This is true for all of drivers/acpi/*.c, with the > exception of drivers/acpi/osl.c, but even some of that source can be cleaned up > to be more Linux-friendly. > > Further rationale is that there is no way to enforce the CAisms in Linux-specific > code. You will frequently find mixed return values. Sometimes a function is > declared as > > acpi_status acpi_foo() > > and return -1 and 0. Or vice versa. > > The ACPI drivers were initially written in the same style that the CA was written, > which makes it confusing when you look at them. But, they don't need to be that > way. They can look like real Linux drivers and become a lot more palatable. > > Eventually, all of the CAisms should be pushed down to the thin layer that sits > above the interpreter. All exported functions should return ints, and those that > deal directly with the CA interface should simply translate the AE_* error > values into an errno return. > > Thanks, > > > Pat Well, I will certainly change the dock code, but pulling this stuff out of the hotplug drivers will take longer since it would require changing the offending acpi interfaces. - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
