From: Andres Salomon Date: Mon, 28 Apr 2008 09:15:03 +0000 (-0700) Subject: PM/gxfb: add hook to PM console layer that allows disabling of suspend VT switch X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=b6f448e99ce7955b9707ed36a46cab2c6ddf7ddc;p=GitHub%2FLineageOS%2Fandroid_kernel_samsung_universal7580.git 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 --- diff --git a/Documentation/fb/gxfb.txt b/Documentation/fb/gxfb.txt index b5609614201..2f640903bbb 100644 --- a/Documentation/fb/gxfb.txt +++ b/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 --git a/drivers/video/geode/gxfb_core.c b/drivers/video/geode/gxfb_core.c index 151d964c025..f16c21d5bc2 100644 --- a/drivers/video/geode/gxfb_core.c +++ b/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 = { @@ -382,6 +384,8 @@ static int __init gxfb_probe(struct pci_dev *pdev, const struct pci_device_id *i 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; @@ -502,5 +506,8 @@ MODULE_PARM_DESC(mode_option, "video mode (x[-][@])"); 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 --git a/include/linux/suspend.h b/include/linux/suspend.h index 1d7d4c5797e..a6977423baf 100644 --- a/include/linux/suspend.h +++ b/include/linux/suspend.h @@ -12,11 +12,22 @@ #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 int pm_prepare_console(void) { return 0; } -static inline void pm_restore_console(void) {} +static inline void pm_set_vt_switch(int do_switch) +{ +} + +static inline int pm_prepare_console(void) +{ + return 0; +} + +static inline void pm_restore_console(void) +{ +} #endif typedef int __bitwise suspend_state_t; diff --git a/kernel/power/console.c b/kernel/power/console.c index 89bcf4973ee..b8628be2a46 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