6.12-stable review patch. If anyone has any objections, please let me know.
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From: Ilpo Järvinen ilpo.jarvinen@linux.intel.com
commit ed2761958ad77e54791802b07095786150eab844 upstream.
The commit f9b11229b79c ("serial: 8250: Fix PM usage_count for console handover") fixed one runtime PM usage counter balance problem that occurs because .dev is not set during univ8250 setup preventing call to pm_runtime_get_sync(). Later, univ8250_console_exit() will trigger the runtime PM usage counter underflow as .dev is already set at that time.
Call pm_runtime_get_sync() to balance the RPM usage counter also in serial8250_register_8250_port() before trying to add the port.
Reported-by: Borislav Petkov (AMD) bp@alien8.de Fixes: bedb404e91bb ("serial: 8250_port: Don't use power management for kernel console") Cc: stable stable@kernel.org Tested-by: Borislav Petkov (AMD) bp@alien8.de Signed-off-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Link: https://lore.kernel.org/r/20241210170120.2231-1-ilpo.jarvinen@linux.intel.co... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/serial/8250/8250_core.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -812,6 +812,9 @@ int serial8250_register_8250_port(const uart->dl_write = up->dl_write;
if (uart->port.type != PORT_8250_CIR) { + if (uart_console_registered(&uart->port)) + pm_runtime_get_sync(uart->port.dev); + if (serial8250_isa_config != NULL) serial8250_isa_config(0, &uart->port, &uart->capabilities);