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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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b6f448e99c
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>
84 lines
1.8 KiB
C
84 lines
1.8 KiB
C
/*
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* drivers/power/process.c - Functions for saving/restoring console.
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*
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* Originally from swsusp.
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*/
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#include <linux/vt_kern.h>
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#include <linux/kbd_kern.h>
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#include <linux/console.h>
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#include <linux/module.h>
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#include "power.h"
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#if defined(CONFIG_VT) && defined(CONFIG_VT_CONSOLE)
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#define SUSPEND_CONSOLE (MAX_NR_CONSOLES-1)
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static int orig_fgconsole, orig_kmsg;
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static int disable_vt_switch;
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/*
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* Normally during a suspend, we allocate a new console and switch to it.
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* When we resume, we switch back to the original console. This switch
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* can be slow, so on systems where the framebuffer can handle restoration
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* of video registers anyways, there's little point in doing the console
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* switch. This function allows you to disable it by passing it '0'.
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*/
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void pm_set_vt_switch(int do_switch)
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{
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acquire_console_sem();
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disable_vt_switch = !do_switch;
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release_console_sem();
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}
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EXPORT_SYMBOL(pm_set_vt_switch);
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int pm_prepare_console(void)
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{
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acquire_console_sem();
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if (disable_vt_switch) {
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release_console_sem();
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return 0;
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}
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orig_fgconsole = fg_console;
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if (vc_allocate(SUSPEND_CONSOLE)) {
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/* we can't have a free VC for now. Too bad,
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* we don't want to mess the screen for now. */
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release_console_sem();
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return 1;
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}
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if (set_console(SUSPEND_CONSOLE)) {
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/*
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* We're unable to switch to the SUSPEND_CONSOLE.
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* Let the calling function know so it can decide
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* what to do.
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*/
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release_console_sem();
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return 1;
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}
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release_console_sem();
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if (vt_waitactive(SUSPEND_CONSOLE)) {
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pr_debug("Suspend: Can't switch VCs.");
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return 1;
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}
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orig_kmsg = kmsg_redirect;
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kmsg_redirect = SUSPEND_CONSOLE;
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return 0;
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}
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void pm_restore_console(void)
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{
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acquire_console_sem();
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if (disable_vt_switch) {
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release_console_sem();
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return;
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}
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set_console(orig_fgconsole);
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release_console_sem();
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kmsg_redirect = orig_kmsg;
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}
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#endif
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