On Friday, June 26, 2015 12:51:39 AM Zheng, Lv wrote: > Hi, Rafael > > > From: Rafael J. Wysocki [mailto:r...@rjwysocki.net] > > Sent: Friday, June 26, 2015 8:44 AM > > > > On Thursday, June 25, 2015 12:43:39 AM Zheng, Lv wrote: > > > Hi, Rafael > > > > > > > From: Rafael J. Wysocki [mailto:r...@rjwysocki.net] > > > > Sent: Thursday, June 25, 2015 7:57 AM > > > > > > > > [cut] > > > > > > > > > > > > +/******************************************************************************* > > > > > + * > > > > > + * FUNCTION: acpi_set_firmware_waking_vector > > > > > + * > > > > > + * PARAMETERS: physical_address - 32-bit physical address of > > > > > ACPI real mode > > > > > + * entry point > > > > > + * physical_address64 - 64-bit physical address of > > > > > ACPI protected > > > > > + * entry point > > > > > + * > > > > > + * RETURN: Status > > > > > + * > > > > > + * DESCRIPTION: Sets the firmware_waking_vector fields of the FACS > > > > > + * > > > > > + > > > > > ******************************************************************************/ > > > > > + > > > > > +acpi_status > > > > > +acpi_set_firmware_waking_vector(acpi_physical_address > > > > > physical_address, > > > > > + acpi_physical_address > > > > > physical_address64) > > > > > > > > The question here is: Why does the host OS need to care about the second > > > > argument of this function that will always be 0? Why didn't you keep > > > > the > > > > old header of acpi_set_firmware_waking_vector() as a one-argument > > > > function > > > > taking a u32 and why didn't you add something like > > > > > > > > acpi_status acpi_set_firmware_waking_vector_full(u32 real_mode_address, > > > > acpi_physical_address > > > > high_address) > > > > > > > > and why didn't you redefine acpi_set_firmware_waking_vector() as > > > > > > > > acpi_status acpi_set_firmware_waking_vector(u32 real_mode_address) > > > > { > > > > return acpi_set_firmware_waking_vector_full(real_mode_address, > > > > 0); > > > > } > > > > > > > > ? > > > > > > > > If you did that, there wouldn't be any need to touch the code in > > > > drivers/acpi/sleep.c and the arch headers, so can you please explain to > > > > me > > > > why *exactly* you didn't do that? > > > > > > Host OS can set non 0 address for both real_mode_address and > > > high_address to indicate that it can support both 32-bit and 64-bit > > resume environments. > > > So if a BIOS favors 32-bit resume environment, it can resume from here; > > > if another BIOS favors 64-bit resume environment, it can > > resume from there. > > > And host OSes can be implemented using only 1 binary to work with both > > > BIOSes. > > > > I'm not talking about that. > > > > It is fine to provide a *new* interface for the OSes that want to do that > > (if any), but *why* is that regarded as a good enough reason for essentially > > *removing* the old interface that Linux (and presumably other OSes too) have > > been using so far? > > Maybe we should ask Bob if we shall just provide a new interfaces for this > and keep the old ones?
Sure, we can talk to Bob about that. > According to my understanding, there is no such example in the ACPICA > upstream. Even so, that doesn't necessarily mean it is be impossible. > Some xxxx_full functions are still pending for being merged by ACPICA > upstream, > they are divergences for now. And it looks like this particular case will become one more divergence of that kind. > > > > We don't want to pass nonzero as high_address anyway, so why are we > > *forced* to > > make pointless changes to non-ACPICA code just to be able to always pass 0 > > as high_address? > > IMO, OSPMs can do this if the cost is not high. > It seems by following your suggestion, we only need to do slight changes in > sleep.c. Which aren't necessary, right? And they don't really make things any better. So I don't see a reason to make them. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
