[PATCH v2 2/2] ACPI: SPCR: Support UART clock frequency field
Markus Probst <[email protected]> Sun, 24 May 2026 22:35:15 +0000
| Newsgroups | org.kernel.vger.linux-efi,org.kernel.vger.linux-acpi,org.kernel.vger.linux-kernel,org.kernel.vger.linux-m68k,org.kernel.vger.linux-mips,org.kernel.vger.linux-serial |
|---|---|
| Message-ID | <[email protected]> |
The Microsoft Serial Port Console Redirection (SPCR) specification revision 1.08 comprises additional field: UART Clock Frequency [1]. It contains a non-zero value indicating the UART clock frequency in Hz. Link: https://learn.microsoft.com/en-us/windows-hardware/drivers/serports/serial-port-console-redirection-table [1] Signed-off-by: Markus Probst <[email protected]> --- drivers/acpi/spcr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c index cfacbe53f279..16f94073fde6 100644 --- a/drivers/acpi/spcr.c +++ b/drivers/acpi/spcr.c @@ -228,7 +228,7 @@ int __init acpi_parse_spcr(bool enable_earlycon, bool enable_console) pr_info("console: %s\n", opts); if (enable_earlycon) - setup_earlycon(opts, 0); + setup_earlycon(opts, table->header.revision >= 3 ? table->uart_clk_freq : 0); if (enable_console) err = add_preferred_console(uart, 0, opts + strlen(uart) + 1); -- 2.53.0