1 files changed, 87 insertions, 0 deletions

diff --git a/drivers/platform/x86/eeepc-laptop.c b/drivers/platform/x86/eeepc-laptop.c
index 5838c69b2fb3..e954f2af5724 100644
--- a/drivers/platform/x86/eeepc-laptop.c
+++ b/drivers/platform/x86/eeepc-laptop.c
@@ -35,6 +35,7 @@
 #include <linux/pci.h>
 #include <linux/pci_hotplug.h>
 #include <linux/leds.h>
+#include <linux/dmi.h>
 
 #define EEEPC_LAPTOP_VERSION    "0.1"
 #define EEEPC_LAPTOP_NAME       "Eee PC Hotkey Driver"
@@ -159,6 +160,7 @@ struct eeepc_laptop {
         acpi_handle handle;             /* the handle of the acpi device */
         u32 cm_supported;               /* the control methods supported
                                            by this BIOS */
+        bool cpufv_disabled;
         u16 event_count[128];           /* count for each event */
 
         struct platform_device *platform_device;
@@ -378,6 +380,8 @@ static ssize_t store_cpufv(struct device *dev,
         struct eeepc_cpufv c;
         int rv, value;
 
+        if (eeepc->cpufv_disabled)
+                return -EPERM;
         if (get_cpufv(eeepc, &c))
                 return -ENODEV;
         rv = parse_arg(buf, count, &value);
@@ -389,6 +393,41 @@ static ssize_t store_cpufv(struct device *dev,
         return rv;
 }
 
+static ssize_t show_cpufv_disabled(struct device *dev,
+                          struct device_attribute *attr,
+                          char *buf)
+{
+        struct eeepc_laptop *eeepc = dev_get_drvdata(dev);
+
+        return sprintf(buf, "%d\n", eeepc->cpufv_disabled);
+}
+
+static ssize_t store_cpufv_disabled(struct device *dev,
+                           struct device_attribute *attr,
+                           const char *buf, size_t count)
+{
+        struct eeepc_laptop *eeepc = dev_get_drvdata(dev);
+        int rv, value;
+
+        rv = parse_arg(buf, count, &value);
+        if (rv < 0)
+                return rv;
+
+        switch (value) {
+        case 0:
+                if (eeepc->cpufv_disabled)
+                        pr_warning("cpufv enabled (not officially supported "
+                                "on this model)\n");
+                eeepc->cpufv_disabled = false;
+                return rv;
+        case 1:
+                return -EPERM;
+        default:
+                return -EINVAL;
+        }
+}
+
+
 static struct device_attribute dev_attr_cpufv = {
         .attr = {
                 .name = "cpufv",
@@ -404,12 +443,22 @@ static struct device_attribute dev_attr_available_cpufv = {
         .show   = show_available_cpufv
 };
 
+static struct device_attribute dev_attr_cpufv_disabled = {
+        .attr = {
+                .name = "cpufv_disabled",
+                .mode = 0644 },
+        .show   = show_cpufv_disabled,
+        .store  = store_cpufv_disabled
+};
+
+
 static struct attribute *platform_attributes[] = {
         &dev_attr_camera.attr,
         &dev_attr_cardr.attr,
         &dev_attr_disp.attr,
         &dev_attr_cpufv.attr,
         &dev_attr_available_cpufv.attr,
+        &dev_attr_cpufv_disabled.attr,
         NULL
 };
 
@@ -1261,6 +1310,42 @@ static void eeepc_acpi_notify(struct acpi_device *device, u32 event)
         }
 }
 
+static void eeepc_dmi_check(struct eeepc_laptop *eeepc)
+{
+        const char *model;
+
+        /*
+         * Blacklist for setting cpufv (cpu speed).
+         *
+         * EeePC 4G ("701") implements CFVS, but it is not supported
+         * by the pre-installed OS, and the original option to change it
+         * in the BIOS setup screen was removed in later versions.
+         *
+         * Judging by the lack of "Super Hybrid Engine" on Asus product pages,
+         * this applies to all "701" models (4G/4G Surf/2G Surf).
+         *
+         * So Asus made a deliberate decision not to support it on this model.
+         * We have several reports that using it can cause the system to hang
+         *
+         * The hang has also been reported on a "702" (Model name "8G"?).
+         *
+         * We avoid dmi_check_system() / dmi_match(), because they use
+         * substring matching.  We don't want to affect the "701SD"
+         * and "701SDX" models, because they do support S.H.E.
+         */
+
+        model = dmi_get_system_info(DMI_PRODUCT_NAME);
+        if (!model)
+                return;
+
+        if (strcmp(model, "701") == 0 || strcmp(model, "702") == 0) {
+                eeepc->cpufv_disabled = true;
+                pr_info("model %s does not officially support setting cpu "
+                        "speed\n", model);
+                pr_info("cpufv disabled to avoid instability\n");
+        }
+}
+
 static void cmsg_quirk(struct eeepc_laptop *eeepc, int cm, const char *name)
 {
         int dummy;
@@ -1342,6 +1427,8 @@ static int __devinit eeepc_acpi_add(struct acpi_device *device)
         strcpy(acpi_device_class(device), EEEPC_ACPI_CLASS);
         device->driver_data = eeepc;
 
+        eeepc_dmi_check(eeepc);
+
         result = eeepc_acpi_init(eeepc, device);
         if (result)
                 goto fail_platform;