From fbbdf7c7d2218e7b88a095ddd0659e38efbe00ab Mon Sep 17 00:00:00 2001
From: Mitsuru IWASAKI <iwasaki@FreeBSD.org>
Date: Thu, 30 Oct 2003 16:14:55 +0000
Subject: [PATCH] Add sysctl MIB and loader tunable `hw.acpi.no_reset_video' as
 the same effect as ACPI_NO_RESET_VIDEO kernel option.

---
 share/man/man4/acpi.4           |  4 ++++
 sys/i386/acpica/acpi_machdep.c  | 10 ++++++++++
 sys/i386/acpica/acpi_wakecode.S |  4 ++++
 sys/i386/acpica/acpi_wakeup.c   |  3 +++
 4 files changed, 21 insertions(+)

diff --git a/share/man/man4/acpi.4 b/share/man/man4/acpi.4
index 43e6e5cd6b8b..576161064b61 100644
--- a/share/man/man4/acpi.4
+++ b/share/man/man4/acpi.4
@@ -319,6 +319,10 @@ the economy power profile.
 Delay in milliseconds to wait for the EC to respond.  Try increasing this
 number if you get the error 
 .Er AE_NO_HARDWARE_RESPONSE .
+.It Va hw.acpi.no_reset_video
+Disables calling the VESA reset BIOS vector on the resume path.  Some
+graphic chips have problems such as LCD white-out after resume.  Try
+setting this to 1 if necessary.
 .It Va hw.acpi.os_name
 Some systems' ASL may have problems because they look for names 
 of Microsoft operating systems.  This tunable overrides the
diff --git a/sys/i386/acpica/acpi_machdep.c b/sys/i386/acpica/acpi_machdep.c
index 09e095ad71ef..18ffdb49850e 100644
--- a/sys/i386/acpica/acpi_machdep.c
+++ b/sys/i386/acpica/acpi_machdep.c
@@ -31,6 +31,8 @@ __FBSDID("$FreeBSD$");
 #include <sys/bus.h>
 #include <sys/conf.h>
 #include <sys/fcntl.h>
+#include <sys/kernel.h>
+#include <sys/sysctl.h>
 #include <sys/uio.h>
 
 #include "acpi.h"
@@ -59,6 +61,9 @@ static device_t	acpi_dev;
 #include <i386/bios/apm.h>
 #endif
 
+u_int32_t acpi_no_reset_video = 0;
+TUNABLE_INT("hw.acpi.no_reset_video", &acpi_no_reset_video);
+
 static struct apm_softc	apm_softc;
 
 static d_open_t apmopen;
@@ -327,6 +332,11 @@ acpi_machdep_init(device_t dev)
 
 	if (intr_model != ACPI_INTR_PIC)
 		acpi_SetIntrModel(intr_model);
+
+	SYSCTL_ADD_UINT(&sc->acpi_sysctl_ctx, SYSCTL_CHILDREN(sc->acpi_sysctl_tree),
+            OID_AUTO, "no_reset_video", CTLFLAG_RD | CTLFLAG_RW, &acpi_no_reset_video, 0,
+	    "Disable calling the VESA reset BIOS vector on the resume path");
+
 	return (0);
 }
 
diff --git a/sys/i386/acpica/acpi_wakecode.S b/sys/i386/acpica/acpi_wakecode.S
index a67f4ad926df..e91a646421d5 100644
--- a/sys/i386/acpica/acpi_wakecode.S
+++ b/sys/i386/acpica/acpi_wakecode.S
@@ -48,12 +48,15 @@ wakeup_16:
 	 * Re-initialize video BIOS.  Restore DS and SS from CS in
 	 * case the BIOS modified them.
 	 */
+	cmp	$1, no_reset_video
+	je	wakeup_16_gdt
 	lcall	$0xc000, $3
 	movw	%cs, %ax
 	movw	%ax, %ds
 	movw	%ax, %ss
 #endif
 
+wakeup_16_gdt:
 	/* Load GDT for real mode */
 	lgdt	physical_gdt
 
@@ -211,6 +214,7 @@ physical_esp:		.long 0
 previous_cr2:		.long 0
 previous_cr3:		.long 0
 previous_cr4:		.long 0
+no_reset_video:		.long 0
 
 /* transfer from real mode to protected mode */
 previous_cr0:		.long 0
diff --git a/sys/i386/acpica/acpi_wakeup.c b/sys/i386/acpica/acpi_wakeup.c
index 9a11f42b2816..adf366ecebe7 100644
--- a/sys/i386/acpica/acpi_wakeup.c
+++ b/sys/i386/acpica/acpi_wakeup.c
@@ -61,6 +61,7 @@ __FBSDID("$FreeBSD$");
 #define	vm_page_unlock_queues()
 #endif
 
+extern u_int32_t acpi_no_reset_video;
 extern void initializecpu(void);
 
 static struct region_descriptor	r_idt, r_gdt, *p_gdt;
@@ -232,6 +233,8 @@ acpi_sleep_machdep(struct acpi_softc *sc, int state)
 		WAKECODE_FIXUP(previous_cr3, u_int32_t, r_cr3);
 		WAKECODE_FIXUP(previous_cr4, u_int32_t, r_cr4);
 
+		WAKECODE_FIXUP(no_reset_video, u_int32_t, acpi_no_reset_video);
+
 		WAKECODE_FIXUP(previous_tr,  u_int16_t, r_tr);
 		WAKECODE_BCOPY(previous_gdt, struct region_descriptor, r_gdt);
 		WAKECODE_FIXUP(previous_ldt, u_int16_t, r_ldt);