On Mon, 18 Jan 2016, Mark Rutland wrote: > On Fri, Jan 15, 2016 at 02:55:14PM +0800, Shannon Zhao wrote: > > From: Shannon Zhao <shannon.zhao@xxxxxxxxxx> > > > > ACPI 6.0 introduces a new table STAO to list the devices which are used > > by Xen and can't be used by Dom0. On Xen virtual platforms, the physical > > UART is used by Xen. So here it hides UART from Dom0. > > > > Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx> > > --- > > CC: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx> (supporter:ACPI) > > CC: Len Brown <lenb@xxxxxxxxxx> (supporter:ACPI) > > CC: linux-acpi@xxxxxxxxxxxxxxx (open list:ACPI) > > --- > > drivers/acpi/bus.c | 30 ++++++++++++++++++++++++++++++ > > 1 file changed, 30 insertions(+) > > > > diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c > > index a212cef..d7a559f 100644 > > --- a/drivers/acpi/bus.c > > +++ b/drivers/acpi/bus.c > > @@ -46,6 +46,7 @@ ACPI_MODULE_NAME("bus"); > > struct acpi_device *acpi_root; > > struct proc_dir_entry *acpi_root_dir; > > EXPORT_SYMBOL(acpi_root_dir); > > +static u64 spcr_uart_addr; > > > > #ifdef CONFIG_X86 > > #ifdef CONFIG_ACPI_CUSTOM_DSDT > > @@ -93,6 +94,17 @@ acpi_status acpi_bus_get_status_handle(acpi_handle handle, > > { > > acpi_status status; > > > > + if (spcr_uart_addr != 0xffffffffffffffff) { > > The SPCR spec says that the Base Address fields being zero means that > console redirection is disabled (though I'm not clear on whether or not > that requires the whole acpi_generic_address to be zero). > > Can we not use that here? Shannon changed the code from 0 to 0xffffffffffffffff following my suggestion to his previous series, but I didn't realize that the SPCR spec says 0 means no console redirection. In that case using 0 is better. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html