Commit 4266e8fa authored by tuhaowen's avatar tuhaowen Committed by Rafael J. Wysocki
Browse files

PM: sleep: console: Fix the black screen issue 



When the computer enters sleep status without a monitor
connected, the system switches the console to the virtual
terminal tty63(SUSPEND_CONSOLE).

If a monitor is subsequently connected before waking up,
the system skips the required VT restoration process
during wake-up, leaving the console on tty63 instead of
switching back to tty1.

To fix this issue, a global flag vt_switch_done is introduced
to record whether the system has successfully switched to
the suspend console via vt_move_to_console() during suspend.

If the switch was completed, vt_switch_done is set to 1.
Later during resume, this flag is checked to ensure that
the original console is restored properly by calling
vt_move_to_console(orig_fgconsole, 0).

This prevents scenarios where the resume logic skips console
restoration due to incorrect detection of the console state,
especially when a monitor is reconnected before waking up.

Signed-off-by: default avatartuhaowen <tuhaowen@uniontech.com>
Link: https://patch.msgid.link/20250611032345.29962-1-tuhaowen@uniontech.com


Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 3e7e5adc

kernel/power/console.c

+6 −1
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#define SUSPEND_CONSOLE	(MAX_NR_CONSOLES-1)



static int orig_fgconsole, orig_kmsg;

static bool vt_switch_done;



static DEFINE_MUTEX(vt_switch_mutex);
@@ -136,17 +137,21 @@ void pm_prepare_console(void) 
	if (orig_fgconsole < 0)

		return;



	vt_switch_done = true;



	orig_kmsg = vt_kmsg_redirect(SUSPEND_CONSOLE);

	return;

}



void pm_restore_console(void)

{

	if (!pm_vt_switch())

	if (!pm_vt_switch() && !vt_switch_done)

		return;



	if (orig_fgconsole >= 0) {

		vt_move_to_console(orig_fgconsole, 0);

		vt_kmsg_redirect(orig_kmsg);

	}



	vt_switch_done = false;

}