From b6f448e99ce7955b9707ed36a46cab2c6ddf7ddc Mon Sep 17 00:00:00 2001 From: Andres Salomon Date: Mon, 28 Apr 2008 02:15:03 -0700 Subject: PM/gxfb: add hook to PM console layer that allows disabling of suspend VT switch Prior to suspend, we allocate and switch to a new VT; after suspend, we switch back to the original VT. This can be slow, and is completely unnecessary if the framebuffer we're using can restore video properly. This adds a hook that allows drivers to select whether or not to do this vt switch, and changes the gxfb driver to call this hook. It also adds a module param to gxfb to allow controlling of the vt switch (defaulting to no switch). (Note: I'm not convinced that console_sem is the best way to protect this, but we should probably have some form of locking..) [akpm@linux-foundation.org: build fix] Signed-off-by: Andres Salomon Cc: Jordan Crouse Cc: "Antonino A. Daplas" Cc: Pavel Machek Cc: "Rafael J. Wysocki" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/power/console.c | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-) (limited to 'kernel/power') diff --git a/kernel/power/console.c b/kernel/power/console.c index 89bcf4973ee5..b8628be2a465 100644 --- a/kernel/power/console.c +++ b/kernel/power/console.c @@ -7,17 +7,39 @@ #include #include #include +#include #include "power.h" #if defined(CONFIG_VT) && defined(CONFIG_VT_CONSOLE) #define SUSPEND_CONSOLE (MAX_NR_CONSOLES-1) static int orig_fgconsole, orig_kmsg; +static int disable_vt_switch; + +/* + * Normally during a suspend, we allocate a new console and switch to it. + * When we resume, we switch back to the original console. This switch + * can be slow, so on systems where the framebuffer can handle restoration + * of video registers anyways, there's little point in doing the console + * switch. This function allows you to disable it by passing it '0'. + */ +void pm_set_vt_switch(int do_switch) +{ + acquire_console_sem(); + disable_vt_switch = !do_switch; + release_console_sem(); +} +EXPORT_SYMBOL(pm_set_vt_switch); int pm_prepare_console(void) { acquire_console_sem(); + if (disable_vt_switch) { + release_console_sem(); + return 0; + } + orig_fgconsole = fg_console; if (vc_allocate(SUSPEND_CONSOLE)) { @@ -50,9 +72,12 @@ int pm_prepare_console(void) void pm_restore_console(void) { acquire_console_sem(); + if (disable_vt_switch) { + release_console_sem(); + return; + } set_console(orig_fgconsole); release_console_sem(); kmsg_redirect = orig_kmsg; - return; } #endif -- cgit v1.2.3