[PATCH v11 2/4] ACPI: parse SPCR and enable matching console

I'm afraid Aleksey is no longer assigned to Linaro (you will probably
have seen a bounce).

On Mon, Sep 11, 2017 at 11:11:49AM +0200, Andreas Schwab wrote:

On Sep 27 2016, Aleksey Makarov [off-list ref] wrote:

quoted

'ARM Server Base Boot Requiremets' [1] mentions SPCR (Serial Port
Console Redirection Table) [2] as a mandatory ACPI table that
specifies the configuration of serial console.

Defer initialization of DT earlycon until ACPI/DT decision is made.

Parse the ACPI SPCR table, setup earlycon if required,
enable specified console.

How can I tell the kernel to ignore this table and use the console on
the command line instead?

I guess we could just ignore the table completely
	if (console_set_on_cmdline)
like its counterpart in of_console_check().

Like so (not tested beyond compile testing):

diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c
index 324b35bfe781..c3cf0f1ebb8f 100644
--- a/drivers/acpi/spcr.c
+++ b/drivers/acpi/spcr.c

@@ -96,6 +96,9 @@ int __init parse_spcr(bool earlycon)
        int baud_rate;

	        int err;

+       if (console_set_on_cmdline)
+               return 0;
+
        if (acpi_disabled)
	                return -ENODEV;

Are you asking because you want to use a different console in a lab
setup or because there are issues with SPCR on your platform?

/
    Leif