Re: [PATCH 2/3] Introduce acpi_root_table=rsdt boot param and dmi list to force rsdt

[Thomas Renninger <trenn@suse.de>]

Updated Patch.

The dmi list was not complete.
http://bugzilla.kernel.org/show_bug.cgi?id=8246
states a R51e which also needs to be added.
IMO the whole [XTR][45]* models which came out at that time should be
added also, this should be rather safe to do.

This one also adds the known broken R50e and another similar BIOS
(1RET*) now.

=========


Introduce acpi_root_table=rsdt boot param and dmi list to force rsdt

Blacklist R40e, R51e and T40, T40p, T41, T41p, T42, T42p, R50 and R50p
ThinkPads to use the RSDT instead of the XSDT.

Signed-off-by: Thomas Renninger <trenn@suse.de>
Tested-by: Mark Doughty <me@markdoughty.co.uk>
CC: Yakui Zhao <yakui.zhao@intel.com>


---
 Documentation/kernel-parameters.txt |    5 +++++
 drivers/acpi/tables.c               |   36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+)

Index: linux-acpi-2.6_video_native_vs_vendor/drivers/acpi/tables.c
===================================================================
--- linux-acpi-2.6_video_native_vs_vendor.orig/drivers/acpi/tables.c
+++ linux-acpi-2.6_video_native_vs_vendor/drivers/acpi/tables.c
@@ -32,6 +32,7 @@
 #include <linux/errno.h>
 #include <linux/acpi.h>
 #include <linux/bootmem.h>
+#include <linux/dmi.h>
 
 #define PREFIX			"ACPI: "
 
@@ -282,6 +283,36 @@ static void __init check_multiple_madt(v
 	return;
 }
 
+static struct dmi_system_id acpi_rsdt_dmi_table[] = {
+	{
+	    .ident = "ThinkPad ", /* R40e, broken C-states */
+	    .matches = {
+		DMI_MATCH(DMI_BIOS_VENDOR, "IBM"),
+		DMI_MATCH(DMI_BIOS_VERSION, "1SET")},
+	},
+	{
+	    .ident = "ThinkPad ", /* R50e, slow booting */
+	    .matches = {
+		DMI_MATCH(DMI_BIOS_VENDOR, "IBM"),
+		DMI_MATCH(DMI_BIOS_VERSION, "1WET")},
+	},
+	{
+	    .ident = "ThinkPad ", /* T40, T40p, T41, T41p, T42, T42p
+				     R50, R50p */
+	    .matches = {
+		DMI_MATCH(DMI_BIOS_VENDOR, "IBM"),
+		DMI_MATCH(DMI_BIOS_VERSION, "1RET")},
+	},
+};
+
+static int __init acpi_force_rsdt(char *opt)
+{
+	if (!strcmp(opt, "rsdt"))
+		acpi_gbl_force_rsdt = 1;
+	return 0;
+}
+early_param("acpi_root_table", acpi_force_rsdt);
+
 /*
  * acpi_table_init()
  *
@@ -293,6 +324,11 @@ static void __init check_multiple_madt(v
 
 int __init acpi_table_init(void)
 {
+	if (dmi_check_system(acpi_rsdt_dmi_table))
+		acpi_gbl_force_rsdt = 1;
+	if (acpi_gbl_force_rsdt)
+		printk(KERN_INFO "Using RSDT as ACPI root table\n");
+
 	acpi_initialize_tables(initial_tables, ACPI_MAX_TABLES, 0);
 	check_multiple_madt();
 	return 0;
Index: linux-acpi-2.6_video_native_vs_vendor/Documentation/kernel-parameters.txt
===================================================================
--- linux-acpi-2.6_video_native_vs_vendor.orig/Documentation/kernel-parameters.txt
+++ linux-acpi-2.6_video_native_vs_vendor/Documentation/kernel-parameters.txt
@@ -230,6 +230,11 @@ and is between 256 and 4096 characters.
 			to assume that this machine's pmtimer latches its value
 			and always returns good values.
 
+	acpi_root_table= [X86,ACPI]
+			{ rsdt }
+			rsdt: Take RSDT address for fetching
+			ACPI tables (instead of XSDT)
+
 	agp=		[AGP]
 			{ off | try_unsupported }
 			off: disable AGP support