#define OSI_STRING_LENGTH_MAX 64 /* arbitrary */
static char osi_additional_string[OSI_STRING_LENGTH_MAX];
-static int osi_linux; /* disable _OSI(Linux) by default */
+/*
+ * "Ode to _OSI(Linux)"
+ *
+ * osi_linux -- Control response to BIOS _OSI(Linux) query.
+ *
+ * As Linux evolves, the features that it supports change.
+ * So an OSI string such as "Linux" is not specific enough
+ * to be useful across multiple versions of Linux. It
+ * doesn't identify any particular feature, interface,
+ * or even any particular version of Linux...
+ *
+ * Unfortunately, Linux-2.6.22 and earlier responded "yes"
+ * to a BIOS _OSI(Linux) query. When
+ * a reference mobile BIOS started using it, its use
+ * started to spread to many vendor platforms.
+ * As it is not supportable, we need to halt that spread.
+ *
+ * Today, most BIOS references to _OSI(Linux) are noise --
+ * they have no functional effect and are just dead code
+ * carried over from the reference BIOS.
+ *
+ * The next most common case is that _OSI(Linux) harms Linux,
+ * usually by causing the BIOS to follow paths that are
+ * not tested during Windows validation.
+ *
+ * Finally, there is a short list of platforms
+ * where OSI(Linux) benefits Linux.
+ *
+ * In Linux-2.6.23, OSI(Linux) is first disabled by default.
+ * DMI is used to disable the dmesg warning about OSI(Linux)
+ * on platforms where it is known to have no effect.
+ * But a dmesg warning remains for systems where
+ * we do not know if OSI(Linux) is good or bad for the system.
+ * DMI is also used to enable OSI(Linux) for the machines
+ * that are known to need it.
+ *
+ * BIOS writers should NOT query _OSI(Linux) on future systems.
+ * It will be ignored by default, and to get Linux to
+ * not ignore it will require a kernel source update to
+ * add a DMI entry, or a boot-time "acpi_osi=Linux" invocation.
+ */
+#define OSI_LINUX_ENABLE 0
+
+struct osi_linux {
+ unsigned int enable:1;
+ unsigned int dmi:1;
+ unsigned int cmdline:1;
+ unsigned int known:1;
+} osi_linux = { OSI_LINUX_ENABLE, 0, 0, 0};
static void __init acpi_request_region (struct acpi_generic_address *addr,
unsigned int length, char *desc)
__setup("acpi_os_name=", acpi_os_name_setup);
-static void enable_osi_linux(int enable) {
+static void __init set_osi_linux(unsigned int enable)
+{
+ if (osi_linux.enable != enable) {
+ osi_linux.enable = enable;
+ printk(KERN_NOTICE PREFIX "%sed _OSI(Linux)\n",
+ enable ? "Add": "Delet");
+ }
+ return;
+}
+
+static void __init acpi_cmdline_osi_linux(unsigned int enable)
+{
+ osi_linux.cmdline = 1; /* cmdline set the default */
+ set_osi_linux(enable);
+
+ return;
+}
+
+void __init acpi_dmi_osi_linux(int enable, const struct dmi_system_id *d)
+{
+ osi_linux.dmi = 1; /* DMI knows that this box asks OSI(Linux) */
+
+ printk(KERN_NOTICE PREFIX "DMI detected: %s\n", d->ident);
+
+ if (enable == -1)
+ return;
+
+ osi_linux.known = 1; /* DMI knows which OSI(Linux) default needed */
- if (osi_linux != enable)
- printk(KERN_INFO PREFIX "%sabled _OSI(Linux)\n",
- enable ? "En": "Dis");
+ set_osi_linux(enable);
- osi_linux = enable;
return;
}
printk(KERN_INFO PREFIX "_OSI method disabled\n");
acpi_gbl_create_osi_method = FALSE;
} else if (!strcmp("!Linux", str)) {
- enable_osi_linux(0);
+ acpi_cmdline_osi_linux(0); /* !enable */
} else if (*str == '!') {
if (acpi_osi_invalidate(++str) == AE_OK)
printk(KERN_INFO PREFIX "Deleted _OSI(%s)\n", str);
} else if (!strcmp("Linux", str)) {
- enable_osi_linux(1);
+ acpi_cmdline_osi_linux(1); /* enable */
} else if (*osi_additional_string == '\0') {
strncpy(osi_additional_string, str, OSI_STRING_LENGTH_MAX);
printk(KERN_INFO PREFIX "Added _OSI(%s)\n", str);
if (!strncmp(osi_additional_string, interface, OSI_STRING_LENGTH_MAX))
return AE_OK;
if (!strcmp("Linux", interface)) {
- printk(KERN_WARNING PREFIX
- "System BIOS is requesting _OSI(Linux)\n");
- if (acpi_dmi_dump())
- printk(KERN_NOTICE PREFIX
- "[please extract dmidecode output]\n");
- printk(KERN_NOTICE PREFIX
- "Please send DMI info above to "
- "linux-acpi@vger.kernel.org\n");
+
printk(KERN_NOTICE PREFIX
- "If \"acpi_osi=%sLinux\" works better, "
- "please notify linux-acpi@vger.kernel.org\n",
- osi_linux ? "!" : "");
- if(osi_linux)
+ "BIOS _OSI(Linux) query %s%s\n",
+ osi_linux.enable ? "honored" : "ignored",
+ osi_linux.cmdline ? " via cmdline" :
+ osi_linux.dmi ? " via DMI" : "");
+
+ if (!osi_linux.dmi) {
+ if (acpi_dmi_dump())
+ printk(KERN_NOTICE PREFIX
+ "[please extract dmidecode output]\n");
+ printk(KERN_NOTICE PREFIX
+ "Please send DMI info above to "
+ "linux-acpi@vger.kernel.org\n");
+ }
+ if (!osi_linux.known && !osi_linux.cmdline) {
+ printk(KERN_NOTICE PREFIX
+ "If \"acpi_osi=%sLinux\" works better, "
+ "please notify linux-acpi@vger.kernel.org\n",
+ osi_linux.enable ? "!" : "");
+ }
+
+ if (osi_linux.enable)
return AE_OK;
}
return AE_SUPPORT;
projects / linux-2.6-omap-h63xx.git / commitdiff