From: Andres Salomon 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..) Signed-off-by: Andres Salomon Cc: Jordan Crouse Cc: "Antonino A. Daplas" Cc: Pavel Machek Cc: "Rafael J. Wysocki" Signed-off-by: Andrew Morton --- Documentation/fb/gxfb.txt | 3 ++- drivers/video/geode/gxfb_core.c | 7 +++++++ include/linux/suspend.h | 2 ++ kernel/power/console.c | 27 ++++++++++++++++++++++++++- 4 files changed, 37 insertions(+), 2 deletions(-) diff -puN Documentation/fb/gxfb.txt~pm-gxfb-add-hook-to-pm-console-layer-that-allows-disabling-of-suspend-vt-switch Documentation/fb/gxfb.txt --- a/Documentation/fb/gxfb.txt~pm-gxfb-add-hook-to-pm-console-layer-that-allows-disabling-of-suspend-vt-switch +++ a/Documentation/fb/gxfb.txt @@ -45,7 +45,8 @@ Accepted options: mode_option - specify the video mode. Of the form x[-][@] vram - size of video ram (normally auto-detected) - +vt_switch - enable vt switching during suspend/resume. The vt + switch is slow, but harmless. -- Andres Salomon diff -puN drivers/video/geode/gxfb_core.c~pm-gxfb-add-hook-to-pm-console-layer-that-allows-disabling-of-suspend-vt-switch drivers/video/geode/gxfb_core.c --- a/drivers/video/geode/gxfb_core.c~pm-gxfb-add-hook-to-pm-console-layer-that-allows-disabling-of-suspend-vt-switch +++ a/drivers/video/geode/gxfb_core.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include #include @@ -37,6 +38,7 @@ static char *mode_option; static int vram; +static int vt_switch; /* Modes relevant to the GX (taken from modedb.c) */ static const struct fb_videomode gx_modedb[] __initdata = { @@ -388,6 +390,8 @@ static int __init gxfb_probe(struct pci_ gxfb_check_var(&info->var, info); gxfb_set_par(info); + pm_set_vt_switch(vt_switch); + if (register_framebuffer(info) < 0) { ret = -EINVAL; goto err; @@ -508,5 +512,8 @@ MODULE_PARM_DESC(mode_option, "video mod module_param(vram, int, 0); MODULE_PARM_DESC(vram, "video memory size"); +module_param(vt_switch, int, 0); +MODULE_PARM_DESC(vt_switch, "enable VT switch during suspend/resume"); + MODULE_DESCRIPTION("Framebuffer driver for the AMD Geode GX"); MODULE_LICENSE("GPL"); diff -puN include/linux/suspend.h~pm-gxfb-add-hook-to-pm-console-layer-that-allows-disabling-of-suspend-vt-switch include/linux/suspend.h --- a/include/linux/suspend.h~pm-gxfb-add-hook-to-pm-console-layer-that-allows-disabling-of-suspend-vt-switch +++ a/include/linux/suspend.h @@ -12,9 +12,11 @@ #include #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_VT) && defined(CONFIG_VT_CONSOLE) +extern void pm_set_vt_switch(int); extern int pm_prepare_console(void); extern void pm_restore_console(void); #else +static inline void pm_set_vt_switch(int) {} static inline int pm_prepare_console(void) { return 0; } static inline void pm_restore_console(void) {} #endif diff -puN kernel/power/console.c~pm-gxfb-add-hook-to-pm-console-layer-that-allows-disabling-of-suspend-vt-switch kernel/power/console.c --- a/kernel/power/console.c~pm-gxfb-add-hook-to-pm-console-layer-that-allows-disabling-of-suspend-vt-switch +++ a/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 _