kernel26-magellan/patches-2.6.21-r4/0157-2.6.21-acpi-dsdt-initrd-0.8.4.patch

diff -urpN -X linux-2.6.21/Documentation/dontdiff linux-2.6.21-rc4.bak/Documentation/dsdt-initrd.txt linux-2.6.21/Documentation/dsdt-initrd.txt
--- linux-2.6.21-rc4.bak/Documentation/dsdt-initrd.txt	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.21/Documentation/dsdt-initrd.txt	2007-03-03 23:06:58.000000000 +0100
@@ -0,0 +1,98 @@
+ACPI Custom DSDT read from initramfs
+
+2003 by Markuss Gaugusch < dsdt at gaugusch dot org >
+Special thanks go to Thomas Renninger from SuSE, who updated the patch for
+2.6.0 and later modified it to read inside initramfs
+2004 - 2007 maintained by Eric Piel < eric dot piel at tremplin-utc dot net >
+
+This option is intended for people who would like to hack their DSDT and don't want
+to recompile their kernel after every change. It can also be useful to distros
+which offers pre-compiled kernels and want to allow their users to use a
+modified DSDT. In the Kernel config, enable the initial RAM filesystem support
+(in Device Drivers|Block Devices) and enable ACPI_CUSTOM_DSDT_INITRD at the ACPI
+options (General Setup|ACPI Support|Read custom DSDT from initrd).
+
+A custom DSDT (Differentiated System Description Table) is useful when your
+computer uses ACPI but problems occur due to broken implementation. Typically,
+your computer works but there are some troubles with the hardware detection or
+the power management. You can check that troubles come from errors in the DSDT by
+activating the ACPI debug option and reading the logs. This table is provided
+by the BIOS, therefore it might be a good idea to check for BIOS update on your
+vendor website before going any further. Errors are often caused by vendors
+testing their hardware only with Windows or because there is code which is
+executed only on a specific OS with a specific version and Linux hasn't been
+considered during the development.
+
+Before you run away from customising your DSDT, you should note that already
+corrected tables are available for a fair amount of computers on this web-page:
+http://acpi.sf.net/dsdt . If you are part of the unluckies who cannot find
+their hardware in this database, you can modify your DSDT by yourself. This
+process is less painful than it sounds. Download the Intel ASL 
+compiler/decompiler at http://www.intel.com/technology/IAPC/acpi/downloads.htm .
+As root, you then have to dump your DSDT and decompile it. By using the
+compiler messages as well as the kernel ACPI debug messages and the reference book
+(available at the Intel website and also at http://www.acpi.info), it is quite
+easy to obtain a fully working table.
+
+Once your new DSDT is ready you'll have to add it to an initrd so that the
+kernel can read the table at the very beginning of the boot. As the file has
+to be accessed very early during the boot process the initrd has to be an
+initramfs. The file is contained into the initramfs under the name /DSDT.aml .
+To obtain such an initrd, you might have to modify your mkinitrd script or you
+can add it later to the initrd with the script appended to this document. The
+command will look like:
+initrd-add-dsdt initrd.img my-dsdt.aml
+
+In case you don't use any initrd, the possibilities you have are to either start
+using one (try mkinitrd or yaird), or use the "Include Custom DSDT" configure
+option to directly include your DSDT inside the kernel.
+
+The message "Looking for DSDT in initramfs..." will tell you if the DSDT was
+found or not. If you need to update your DSDT, generate a new initrd and
+perform the steps above. Don't forget that with Lilo, you'll have to re-run it.
+
+
+======================= Here starts initrd-add-dsdt ===============================
+#!/bin/bash
+# Adds a DSDT file to the initrd (if it's an initramfs)
+# first argument is the name of archive
+# second argurment is the name of the file to add
+# The file will be copied as /DSDT.aml
+
+# 20060126: fix "Premature end of file" with some old cpio (Roland Robic)
+# 20060205: this time it should really work
+
+# check the arguments
+if [ $# -ne 2 ]; then
+	program_name=$(basename $0)
+	echo "\
+$program_name: too few arguments
+Usage: $program_name initrd-name.img DSDT-to-add.aml
+Adds a DSDT file to an initrd (in initramfs format)
+
+  initrd-name.img: filename of the initrd in initramfs format
+  DSDT-to-add.aml: filename of the DSDT file to add
+  " 1>&2
+    exit 1
+fi
+
+# we should check it's an initramfs
+
+tempcpio=$(mktemp -d)
+# cleanup on exit, hangup, interrupt, quit, termination
+trap 'rm -rf $tempcpio' 0 1 2 3 15
+
+# extract the archive
+gunzip -c "$1" > "$tempcpio"/initramfs.cpio || exit 1
+
+# copy the DSDT file at the root of the directory so that we can call it "/DSDT.aml"
+cp -f "$2" "$tempcpio"/DSDT.aml
+
+# add the file
+cd "$tempcpio"
+(echo DSDT.aml | cpio --quiet -H newc -o -A -O "$tempcpio"/initramfs.cpio) || exit 1
+cd "$OLDPWD"
+
+# re-compress the archive
+gzip -c "$tempcpio"/initramfs.cpio > "$1"
+
diff -urpN -X linux-2.6.21/Documentation/dontdiff linux-2.6.21-rc4.bak/drivers/acpi/Kconfig linux-2.6.21/drivers/acpi/Kconfig
--- linux-2.6.21-rc4.bak/drivers/acpi/Kconfig	2007-03-18 12:58:03.000000000 +0100
+++ linux-2.6.21/drivers/acpi/Kconfig	2007-03-17 01:28:53.000000000 +0100
@@ -298,6 +298,23 @@ config ACPI_CUSTOM_DSDT_FILE
 	  Enter the full path name to the file which includes the AmlCode
 	  declaration.
 
+config ACPI_CUSTOM_DSDT_INITRD
+	bool "Read Custom DSDT from initramfs"
+	depends on BLK_DEV_INITRD
+	default y
+	help
+	  The DSDT (Differentiated System Description Table) often needs to be
+	  overridden because of broken BIOS implementations. If this feature is
+	  activated you will be able to provide a customized DSDT by adding it
+	  to your initramfs.  For now you need to use a special mkinitrd tool.
+	  For more details see <file:Documentation/dsdt-initrd.txt> or 
+	  <http://gaugusch.at/kernel.shtml>. If there is no table found, it 
+	  will fallback to the custom DSDT in-kernel (if activated) or to the
+	  DSDT from the BIOS.
+
+	  Even if you do not need a new one at the moment, you may want to use a
+	  better implemented DSDT later. It is safe to say Y here.
+
 config ACPI_BLACKLIST_YEAR
 	int "Disable ACPI for systems before Jan 1st this year" if X86_32
 	default 0
diff -urpN -X linux-2.6.21/Documentation/dontdiff linux-2.6.21-rc4.bak/drivers/acpi/osl.c linux-2.6.21/drivers/acpi/osl.c
--- linux-2.6.21-rc4.bak/drivers/acpi/osl.c	2007-03-18 12:55:13.000000000 +0100
+++ linux-2.6.21/drivers/acpi/osl.c	2007-03-17 10:26:06.000000000 +0100
@@ -256,6 +256,67 @@ acpi_os_predefined_override(const struct
 	return AE_OK;
 }
 
+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
+struct acpi_table_header * acpi_find_dsdt_initrd(void)
+{
+	struct file *firmware_file;
+	mm_segment_t oldfs;
+	unsigned long len, len2;
+	struct acpi_table_header *dsdt_buffer, *ret = NULL;
+	struct kstat stat;
+	/* maybe this could be an argument on the cmd line, but let's keep it simple for now */
+	char *ramfs_dsdt_name = "/DSDT.aml";
+
+	printk(KERN_INFO PREFIX "Looking for DSDT in initramfs... ");
+
+	/* 
+	 * Never do this at home, only the user-space is allowed to open a file.
+	 * The clean way would be to use the firmware loader. But this code must be run
+	 * before there is any userspace available. So we need a static/init firmware 
+	 * infrastructure, which doesn't exist yet...
+	 */
+	if (vfs_stat(ramfs_dsdt_name, &stat) < 0) {
+		printk("error, file %s not found.\n", ramfs_dsdt_name);
+		return ret;
+	}
+
+	len = stat.size;
+	/* check especially against empty files */
+	if (len <= 4) {
+		printk("error file is too small, only %lu bytes.\n", len);
+		return ret;
+	}
+
+	firmware_file = filp_open(ramfs_dsdt_name, O_RDONLY, 0);
+	if (IS_ERR(firmware_file)) {
+		printk("error, could not open file %s.\n", ramfs_dsdt_name);
+		return ret;
+	}
+
+	dsdt_buffer = ACPI_ALLOCATE(len);
+	if (!dsdt_buffer) {
+		printk("error when allocating %lu bytes of memory.\n", len);
+		goto err;
+	}
+
+	oldfs = get_fs();
+	set_fs(KERNEL_DS);
+	len2 = vfs_read(firmware_file, (char __user *)dsdt_buffer, len, &firmware_file->f_pos);
+	set_fs(oldfs);
+	if (len2 < len) {
+		printk("error trying to read %lu bytes from %s.\n", len, ramfs_dsdt_name);
+		ACPI_FREE(dsdt_buffer);
+		goto err;
+	}
+
+	printk("successfully read %lu bytes from %s.\n", len, ramfs_dsdt_name);
+	ret = dsdt_buffer;
+err:
+	filp_close(firmware_file, NULL);
+	return ret;
+}
+#endif
+
 acpi_status
 acpi_os_table_override(struct acpi_table_header * existing_table,
 		       struct acpi_table_header ** new_table)
@@ -263,13 +324,18 @@ acpi_os_table_override(struct acpi_table
 	if (!existing_table || !new_table)
 		return AE_BAD_PARAMETER;
 
+	*new_table = NULL;
+
 #ifdef CONFIG_ACPI_CUSTOM_DSDT
 	if (strncmp(existing_table->signature, "DSDT", 4) == 0)
 		*new_table = (struct acpi_table_header *)AmlCode;
-	else
-		*new_table = NULL;
-#else
-	*new_table = NULL;
+#endif
+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
+	if (strncmp(existing_table->signature, "DSDT", 4) == 0) {
+		struct acpi_table_header* initrd_table = acpi_find_dsdt_initrd();
+		if (initrd_table)
+			*new_table = initrd_table;
+	}
 #endif
 	return AE_OK;
 }
diff -urpN -X linux-2.6.21/Documentation/dontdiff linux-2.6.21-rc4.bak/init/initramfs.c linux-2.6.21/init/initramfs.c
--- linux-2.6.21-rc4.bak/init/initramfs.c	2007-03-18 12:56:47.000000000 +0100
+++ linux-2.6.21/init/initramfs.c	2007-03-03 23:07:05.000000000 +0100
@@ -541,6 +541,26 @@ skip:
 
 #endif
 
+/* Tries to read the initramfs if it's already there, for ACPI Table Overiding */
+void __init early_populate_rootfs(void)
+{
+	char *err = unpack_to_rootfs(__initramfs_start,
+			 __initramfs_end - __initramfs_start, 0);
+	if (err)
+		return;
+#ifdef CONFIG_BLK_DEV_INITRD
+	if (initrd_start) {
+		printk(KERN_INFO "Early unpacking initramfs...");
+		err = unpack_to_rootfs((char *)initrd_start,
+			initrd_end - initrd_start, 0);
+		if (err)
+			return;
+		printk(" done\n");
+	}
+#endif
+	return;
+}
+
 static int __init populate_rootfs(void)
 {
 	char *err = unpack_to_rootfs(__initramfs_start,
diff -urpN -X linux-2.6.21/Documentation/dontdiff linux-2.6.21-rc4.bak/init/main.c linux-2.6.21/init/main.c
--- linux-2.6.21-rc4.bak/init/main.c	2007-03-18 12:56:47.000000000 +0100
+++ linux-2.6.21/init/main.c	2007-03-03 23:07:05.000000000 +0100
@@ -97,8 +97,14 @@ extern void free_initmem(void);
 extern void prepare_namespace(void);
 #ifdef	CONFIG_ACPI
 extern void acpi_early_init(void);
+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
+extern void early_populate_rootfs(void);
+#endif
 #else
 static inline void acpi_early_init(void) { }
+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
+static inline void early_populate_rootfs(void) { }
+#endif
 #endif
 #ifndef CONFIG_DEBUG_RODATA
 static inline void mark_rodata_ro(void) { }
@@ -635,6 +637,9 @@ asmlinkage void __init start_kernel(void
 
 	check_bugs();

+	#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD 
+	early_populate_rootfs(); /* For DSDT override from initramfs */
+	#endif
 	acpi_early_init(); /* before LAPIC and SMP init */
 
 	/* Do the rest non-__init'ed, we're now alive */
1	diff -urpN -X linux-2.6.21/Documentation/dontdiff linux-2.6.21-rc4.bak/Documentation/dsdt-initrd.txt linux-2.6.21/Documentation/dsdt-initrd.txt
2	--- linux-2.6.21-rc4.bak/Documentation/dsdt-initrd.txt 1970-01-01 01:00:00.000000000 +0100
3	+++ linux-2.6.21/Documentation/dsdt-initrd.txt 2007-03-03 23:06:58.000000000 +0100
4	@@ -0,0 +1,98 @@
5	+ACPI Custom DSDT read from initramfs
6	+
7	+2003 by Markuss Gaugusch < dsdt at gaugusch dot org >
8	+Special thanks go to Thomas Renninger from SuSE, who updated the patch for
9	+2.6.0 and later modified it to read inside initramfs
10	+2004 - 2007 maintained by Eric Piel < eric dot piel at tremplin-utc dot net >
11	+
12	+This option is intended for people who would like to hack their DSDT and don't want
13	+to recompile their kernel after every change. It can also be useful to distros
14	+which offers pre-compiled kernels and want to allow their users to use a
15	+modified DSDT. In the Kernel config, enable the initial RAM filesystem support
16	+(in Device Drivers\|Block Devices) and enable ACPI_CUSTOM_DSDT_INITRD at the ACPI
17	+options (General Setup\|ACPI Support\|Read custom DSDT from initrd).
18	+
19	+A custom DSDT (Differentiated System Description Table) is useful when your
20	+computer uses ACPI but problems occur due to broken implementation. Typically,
21	+your computer works but there are some troubles with the hardware detection or
22	+the power management. You can check that troubles come from errors in the DSDT by
23	+activating the ACPI debug option and reading the logs. This table is provided
24	+by the BIOS, therefore it might be a good idea to check for BIOS update on your
25	+vendor website before going any further. Errors are often caused by vendors
26	+testing their hardware only with Windows or because there is code which is
27	+executed only on a specific OS with a specific version and Linux hasn't been
28	+considered during the development.
29	+
30	+Before you run away from customising your DSDT, you should note that already
31	+corrected tables are available for a fair amount of computers on this web-page:
32	+http://acpi.sf.net/dsdt . If you are part of the unluckies who cannot find
33	+their hardware in this database, you can modify your DSDT by yourself. This
34	+process is less painful than it sounds. Download the Intel ASL
35	+compiler/decompiler at http://www.intel.com/technology/IAPC/acpi/downloads.htm .
36	+As root, you then have to dump your DSDT and decompile it. By using the
37	+compiler messages as well as the kernel ACPI debug messages and the reference book
38	+(available at the Intel website and also at http://www.acpi.info), it is quite
39	+easy to obtain a fully working table.
40	+
41	+Once your new DSDT is ready you'll have to add it to an initrd so that the
42	+kernel can read the table at the very beginning of the boot. As the file has
43	+to be accessed very early during the boot process the initrd has to be an
44	+initramfs. The file is contained into the initramfs under the name /DSDT.aml .
45	+To obtain such an initrd, you might have to modify your mkinitrd script or you
46	+can add it later to the initrd with the script appended to this document. The
47	+command will look like:
48	+initrd-add-dsdt initrd.img my-dsdt.aml
49	+
50	+In case you don't use any initrd, the possibilities you have are to either start
51	+using one (try mkinitrd or yaird), or use the "Include Custom DSDT" configure
52	+option to directly include your DSDT inside the kernel.
53	+
54	+The message "Looking for DSDT in initramfs..." will tell you if the DSDT was
55	+found or not. If you need to update your DSDT, generate a new initrd and
56	+perform the steps above. Don't forget that with Lilo, you'll have to re-run it.
57	+
58	+
59	+======================= Here starts initrd-add-dsdt ===============================
60	+#!/bin/bash
61	+# Adds a DSDT file to the initrd (if it's an initramfs)
62	+# first argument is the name of archive
63	+# second argurment is the name of the file to add
64	+# The file will be copied as /DSDT.aml
65	+
66	+# 20060126: fix "Premature end of file" with some old cpio (Roland Robic)
67	+# 20060205: this time it should really work
68	+
69	+# check the arguments
70	+if [ $# -ne 2 ]; then
71	+ program_name=$(basename $0)
72	+ echo "\
73	+$program_name: too few arguments
74	+Usage: $program_name initrd-name.img DSDT-to-add.aml
75	+Adds a DSDT file to an initrd (in initramfs format)
76	+
77	+ initrd-name.img: filename of the initrd in initramfs format
78	+ DSDT-to-add.aml: filename of the DSDT file to add
79	+ " 1>&2
80	+ exit 1
81	+fi
82	+
83	+# we should check it's an initramfs
84	+
85	+tempcpio=$(mktemp -d)
86	+# cleanup on exit, hangup, interrupt, quit, termination
87	+trap 'rm -rf $tempcpio' 0 1 2 3 15
88	+
89	+# extract the archive
90	+gunzip -c "$1" > "$tempcpio"/initramfs.cpio \|\| exit 1
91	+
92	+# copy the DSDT file at the root of the directory so that we can call it "/DSDT.aml"
93	+cp -f "$2" "$tempcpio"/DSDT.aml
94	+
95	+# add the file
96	+cd "$tempcpio"
97	+(echo DSDT.aml \| cpio --quiet -H newc -o -A -O "$tempcpio"/initramfs.cpio) \|\| exit 1
98	+cd "$OLDPWD"
99	+
100	+# re-compress the archive
101	+gzip -c "$tempcpio"/initramfs.cpio > "$1"
102	+
103	diff -urpN -X linux-2.6.21/Documentation/dontdiff linux-2.6.21-rc4.bak/drivers/acpi/Kconfig linux-2.6.21/drivers/acpi/Kconfig
104	--- linux-2.6.21-rc4.bak/drivers/acpi/Kconfig 2007-03-18 12:58:03.000000000 +0100
105	+++ linux-2.6.21/drivers/acpi/Kconfig 2007-03-17 01:28:53.000000000 +0100
106	@@ -298,6 +298,23 @@ config ACPI_CUSTOM_DSDT_FILE
107	Enter the full path name to the file which includes the AmlCode
108	declaration.
109
110	+config ACPI_CUSTOM_DSDT_INITRD
111	+ bool "Read Custom DSDT from initramfs"
112	+ depends on BLK_DEV_INITRD
113	+ default y
114	+ help
115	+ The DSDT (Differentiated System Description Table) often needs to be
116	+ overridden because of broken BIOS implementations. If this feature is
117	+ activated you will be able to provide a customized DSDT by adding it
118	+ to your initramfs. For now you need to use a special mkinitrd tool.
119	+ For more details see <file:Documentation/dsdt-initrd.txt> or
120	+ <http://gaugusch.at/kernel.shtml>. If there is no table found, it
121	+ will fallback to the custom DSDT in-kernel (if activated) or to the
122	+ DSDT from the BIOS.
123	+
124	+ Even if you do not need a new one at the moment, you may want to use a
125	+ better implemented DSDT later. It is safe to say Y here.
126	+
127	config ACPI_BLACKLIST_YEAR
128	int "Disable ACPI for systems before Jan 1st this year" if X86_32
129	default 0
130	diff -urpN -X linux-2.6.21/Documentation/dontdiff linux-2.6.21-rc4.bak/drivers/acpi/osl.c linux-2.6.21/drivers/acpi/osl.c
131	--- linux-2.6.21-rc4.bak/drivers/acpi/osl.c 2007-03-18 12:55:13.000000000 +0100
132	+++ linux-2.6.21/drivers/acpi/osl.c 2007-03-17 10:26:06.000000000 +0100
133	@@ -256,6 +256,67 @@ acpi_os_predefined_override(const struct
134	return AE_OK;
135	}
136
137	+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
138	+struct acpi_table_header * acpi_find_dsdt_initrd(void)
139	+{
140	+ struct file *firmware_file;
141	+ mm_segment_t oldfs;
142	+ unsigned long len, len2;
143	+ struct acpi_table_header dsdt_buffer, ret = NULL;
144	+ struct kstat stat;
145	+ /* maybe this could be an argument on the cmd line, but let's keep it simple for now */
146	+ char *ramfs_dsdt_name = "/DSDT.aml";
147	+
148	+ printk(KERN_INFO PREFIX "Looking for DSDT in initramfs... ");
149	+
150	+ /*
151	+ * Never do this at home, only the user-space is allowed to open a file.
152	+ * The clean way would be to use the firmware loader. But this code must be run
153	+ * before there is any userspace available. So we need a static/init firmware
154	+ * infrastructure, which doesn't exist yet...
155	+ */
156	+ if (vfs_stat(ramfs_dsdt_name, &stat) < 0) {
157	+ printk("error, file %s not found.\n", ramfs_dsdt_name);
158	+ return ret;
159	+ }
160	+
161	+ len = stat.size;
162	+ /* check especially against empty files */
163	+ if (len <= 4) {
164	+ printk("error file is too small, only %lu bytes.\n", len);
165	+ return ret;
166	+ }
167	+
168	+ firmware_file = filp_open(ramfs_dsdt_name, O_RDONLY, 0);
169	+ if (IS_ERR(firmware_file)) {
170	+ printk("error, could not open file %s.\n", ramfs_dsdt_name);
171	+ return ret;
172	+ }
173	+
174	+ dsdt_buffer = ACPI_ALLOCATE(len);
175	+ if (!dsdt_buffer) {
176	+ printk("error when allocating %lu bytes of memory.\n", len);
177	+ goto err;
178	+ }
179	+
180	+ oldfs = get_fs();
181	+ set_fs(KERNEL_DS);
182	+ len2 = vfs_read(firmware_file, (char __user *)dsdt_buffer, len, &firmware_file->f_pos);
183	+ set_fs(oldfs);
184	+ if (len2 < len) {
185	+ printk("error trying to read %lu bytes from %s.\n", len, ramfs_dsdt_name);
186	+ ACPI_FREE(dsdt_buffer);
187	+ goto err;
188	+ }
189	+
190	+ printk("successfully read %lu bytes from %s.\n", len, ramfs_dsdt_name);
191	+ ret = dsdt_buffer;
192	+err:
193	+ filp_close(firmware_file, NULL);
194	+ return ret;
195	+}
196	+#endif
197	+
198	acpi_status
199	acpi_os_table_override(struct acpi_table_header * existing_table,
200	struct acpi_table_header ** new_table)
201	@@ -263,13 +324,18 @@ acpi_os_table_override(struct acpi_table
202	if (!existing_table \|\| !new_table)
203	return AE_BAD_PARAMETER;
204
205	+ *new_table = NULL;
206	+
207	#ifdef CONFIG_ACPI_CUSTOM_DSDT
208	if (strncmp(existing_table->signature, "DSDT", 4) == 0)
209	new_table = (struct acpi_table_header )AmlCode;
210	- else
211	- *new_table = NULL;
212	-#else
213	- *new_table = NULL;
214	+#endif
215	+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
216	+ if (strncmp(existing_table->signature, "DSDT", 4) == 0) {
217	+ struct acpi_table_header* initrd_table = acpi_find_dsdt_initrd();
218	+ if (initrd_table)
219	+ *new_table = initrd_table;
220	+ }
221	#endif
222	return AE_OK;
223	}
224	diff -urpN -X linux-2.6.21/Documentation/dontdiff linux-2.6.21-rc4.bak/init/initramfs.c linux-2.6.21/init/initramfs.c
225	--- linux-2.6.21-rc4.bak/init/initramfs.c 2007-03-18 12:56:47.000000000 +0100
226	+++ linux-2.6.21/init/initramfs.c 2007-03-03 23:07:05.000000000 +0100
227	@@ -541,6 +541,26 @@ skip:
228
229	#endif
230
231	+/* Tries to read the initramfs if it's already there, for ACPI Table Overiding */
232	+void __init early_populate_rootfs(void)
233	+{
234	+ char *err = unpack_to_rootfs(__initramfs_start,
235	+ __initramfs_end - __initramfs_start, 0);
236	+ if (err)
237	+ return;
238	+#ifdef CONFIG_BLK_DEV_INITRD
239	+ if (initrd_start) {
240	+ printk(KERN_INFO "Early unpacking initramfs...");
241	+ err = unpack_to_rootfs((char *)initrd_start,
242	+ initrd_end - initrd_start, 0);
243	+ if (err)
244	+ return;
245	+ printk(" done\n");
246	+ }
247	+#endif
248	+ return;
249	+}
250	+
251	static int __init populate_rootfs(void)
252	{
253	char *err = unpack_to_rootfs(__initramfs_start,
254	diff -urpN -X linux-2.6.21/Documentation/dontdiff linux-2.6.21-rc4.bak/init/main.c linux-2.6.21/init/main.c
255	--- linux-2.6.21-rc4.bak/init/main.c 2007-03-18 12:56:47.000000000 +0100
256	+++ linux-2.6.21/init/main.c 2007-03-03 23:07:05.000000000 +0100
257	@@ -97,8 +97,14 @@ extern void free_initmem(void);
258	extern void prepare_namespace(void);
259	#ifdef CONFIG_ACPI
260	extern void acpi_early_init(void);
261	+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
262	+extern void early_populate_rootfs(void);
263	+#endif
264	#else
265	static inline void acpi_early_init(void) { }
266	+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
267	+static inline void early_populate_rootfs(void) { }
268	+#endif
269	#endif
270	#ifndef CONFIG_DEBUG_RODATA
271	static inline void mark_rodata_ro(void) { }
272	@@ -635,6 +637,9 @@ asmlinkage void __init start_kernel(void
273
274	check_bugs();
275
276	+ #ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
277	+ early_populate_rootfs(); /* For DSDT override from initramfs */
278	+ #endif
279	acpi_early_init(); /* before LAPIC and SMP init */
280
281	/* Do the rest non-__init'ed, we're now alive */