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author | Andres Salomon <dilinger@queued.net> | 2008-04-28 02:15:03 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-28 08:58:36 -0700 |
commit | b6f448e99ce7955b9707ed36a46cab2c6ddf7ddc (patch) | |
tree | 74ae26692c1fd713a0178faca99dea6761d442e8 /kernel/power | |
parent | 46fb6f110dfc3fc99f44cf701f66ea3e790b6a81 (diff) | |
download | kernel_samsung_smdk4412-b6f448e99ce7955b9707ed36a46cab2c6ddf7ddc.zip kernel_samsung_smdk4412-b6f448e99ce7955b9707ed36a46cab2c6ddf7ddc.tar.gz kernel_samsung_smdk4412-b6f448e99ce7955b9707ed36a46cab2c6ddf7ddc.tar.bz2 |
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 <dilinger@debian.org>
Cc: Jordan Crouse <jordan.crouse@amd.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/power')
-rw-r--r-- | kernel/power/console.c | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/kernel/power/console.c b/kernel/power/console.c index 89bcf49..b8628be 100644 --- a/kernel/power/console.c +++ b/kernel/power/console.c @@ -7,17 +7,39 @@ #include <linux/vt_kern.h> #include <linux/kbd_kern.h> #include <linux/console.h> +#include <linux/module.h> #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 |