On Sun, Sep 14, 2014 at 09:14:04PM -0700, Grant Likely wrote: > On Mon, 01 Sep 2014 19:11:44 +0200, Arnd Bergmann <arnd@xxxxxxxx> wrote: > > > > + config->phy_interface = PHY_INTERFACE_MODE_MII; > > > > + config->flags |= SMSC911X_USE_32BIT; > > > > + config->irq_polarity = SMSC911X_IRQ_POLARITY_ACTIVE_HIGH; > > > > + config->irq_type = SMSC911X_IRQ_TYPE_PUSH_PULL; > > > > + return 0; > > > > +} ... > > There is of course the possibility to set those values based on the > > acpi_device_id, but that is exactly the part that _DSD is trying to > > avoid. > These are merely defaults. DSD parsing, when implemented, would be > override these default values. One note of caution here: I do agree that default settings are good but it's worth having clear rules for how we pick the defaults, and advice for maintainers on how to pick those rules. If there's a default people often want to pick it to match their particular system and it can sometimes be hard for the maintainer to identify if a given tweak someone is proposing in the defaults might break some other existing system. Having clear guidelines for picking the defaults avoids arguments and breakage. The two basic rules I've seen are that we either follow the defaults the hardware has after reset or we follow the state the hardware is left in when the kernel starts. Neither is perfect and sometimes the bootloader option just doesn't make sense at all but they're at least clear and simple to understand. It's not the end of the world to do something else, and sometimes the way systems are done just doesn't lend itself to providing clear rules, but if we encourage people to set them they can save grief.
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