Hi Laurent, On Sat, Nov 18, 2023 at 08:50:49PM +0200, Laurent Pinchart wrote: > Hi Sakari, > > Thank you for the patch. > > On Fri, Nov 17, 2023 at 01:14:29PM +0200, Sakari Ailus wrote: > > Document that acpi_dev_state_d0() can be used to tell if the device was > > powered on for probe. > > > > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> > > --- > > Documentation/firmware-guide/acpi/non-d0-probe.rst | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/Documentation/firmware-guide/acpi/non-d0-probe.rst b/Documentation/firmware-guide/acpi/non-d0-probe.rst > > index 7afd16701a02..815bcc8db69f 100644 > > --- a/Documentation/firmware-guide/acpi/non-d0-probe.rst > > +++ b/Documentation/firmware-guide/acpi/non-d0-probe.rst > > @@ -24,6 +24,14 @@ there's a problem with the device, the driver likely probes just fine but the > > first user will find out the device doesn't work, instead of a failure at probe > > time. This feature should thus be used sparingly. > > > > +ACPI framework > > +-------------- > > + > > +Use the Linux ACPI framework function :c:func:`acpi_dev_state_d0()` to tell > > +whether the device was powered on for probe. :c:func:`acpi_dev_state_d0()` > > +returns true if the device is powered on, false otherwise. For non-ACPI backed > > +devices it returns true always. > > + > > While this is true, I don't want to see drivers having to call > ACPI-specific functions, the same way you dislike OF-specific functions > in drivers. Please find a better way to handle this. The functionality is only available on ACPI and the function does the right thing on non-ACPI platforms. I don't see an issue here. Feel free to post DT binding patches on suggested device power state during probe. :-) I think DT would benefit from this as well: the at24 driver is widely used and suddenly making probe() not talk to the chip (or even power it up) at all would probably be seen as a regression. > > > I²C > > --- > > > -- Regards, Sakari Ailus
