Re: [PATCH v1 3/3] x86: acpi: Let OS know that console already had been initialized

[Bin Meng]

On Wed, Apr 15, 2020 at 10:20 PM Bin Meng  wrote:
>
> On Thu, Feb 27, 2020 at 11:22 PM Andy Shevchenko
>  wrote:
> >
> > SPCR has no clue if the UART base clock speed is different to
> > the default one. However, the SPCR 1.04 defines baud rate 0 as
> > a preconfigured state of UART and OS is supposed not to touch
> > the configuration of the serial device.
> >
> > Linux kernel supports that starting from v5.0, see commit
> > b413b1abeb21 ("ACPI: SPCR: Consider baud rate 0 as preconfigured state")
> > for the details.
> >
> > Signed-off-by: Andy Shevchenko 
> > ---
> >  arch/x86/lib/acpi_table.c | 9 +
> >  1 file changed, 9 insertions(+)
> >
>
> Reviewed-by: Bin Meng 

applied to u-boot-x86, thanks!

Re: [PATCH v1 3/3] x86: acpi: Let OS know that console already had been initialized

[Bin Meng]

On Thu, Feb 27, 2020 at 11:22 PM Andy Shevchenko
 wrote:
>
> SPCR has no clue if the UART base clock speed is different to
> the default one. However, the SPCR 1.04 defines baud rate 0 as
> a preconfigured state of UART and OS is supposed not to touch
> the configuration of the serial device.
>
> Linux kernel supports that starting from v5.0, see commit
> b413b1abeb21 ("ACPI: SPCR: Consider baud rate 0 as preconfigured state")
> for the details.
>
> Signed-off-by: Andy Shevchenko 
> ---
>  arch/x86/lib/acpi_table.c | 9 +
>  1 file changed, 9 insertions(+)
>

Reviewed-by: Bin Meng 

[PATCH v1 3/3] x86: acpi: Let OS know that console already had been initialized

[Andy Shevchenko]

SPCR has no clue if the UART base clock speed is different to
the default one. However, the SPCR 1.04 defines baud rate 0 as
a preconfigured state of UART and OS is supposed not to touch
the configuration of the serial device.

Linux kernel supports that starting from v5.0, see commit
b413b1abeb21 ("ACPI: SPCR: Consider baud rate 0 as preconfigured state")
for the details.

Signed-off-by: Andy Shevchenko 
---
 arch/x86/lib/acpi_table.c | 9 +
 1 file changed, 9 insertions(+)

diff --git a/arch/x86/lib/acpi_table.c b/arch/x86/lib/acpi_table.c
index 66e32f21bd..074987e294 100644
--- a/arch/x86/lib/acpi_table.c
+++ b/arch/x86/lib/acpi_table.c
@@ -471,6 +471,15 @@ static void acpi_create_spcr(struct acpi_spcr *spcr)
spcr->pci_device_id = 0x;
spcr->pci_vendor_id = 0x;
 
+   /*
+* SPCR has no clue if the UART base clock speed is different
+* to the default one. However, the SPCR 1.04 defines baud rate
+* 0 as a preconfigured state of UART and OS is supposed not
+* to touch the configuration of the serial device.
+*/
+   if (serial_info.clock != SERIAL_DEFAULT_CLOCK)
+   spcr->baud_rate = 0;
+
/* Fix checksum */
header->checksum = table_compute_checksum((void *)spcr, header->length);
 }
-- 
2.25.0