Merge branch 'develop'

This reverts commit 11ddd3469f.

Makefile

@@ -13,5 +13,4 @@ clean:
 
 load:
 	-/sbin/rmmod $(modname)
-	/sbin/modprobe wmi
 	/sbin/insmod $(modname).ko

NEWS

@@ -1,3 +1,11 @@
+Version 0.4.2 - 26 April 2012
+
+* Fixed a documentation error on unload_state.
+* Added Makefile.dkms and documentation for easier installation using DKMS.
+* Make /proc/acpi/bbswitch world-writable
+* Fix NULL pointer dereference when reporting a failure during ACPI method
+  evaluation.
+
 Version 0.4.1 - 16 January 2012
 
 * Corrected a small error that yielded an confusing error message "The discrete

README.md

@@ -80,7 +80,7 @@ The module has some options that control the behavior on loading and unloading:
 `load_state` and `unload_state`. Valid values are `-1`, `0` and `1` meaning "do
 not change the card state", "turn the card off" and "turn the card on"
 respectively. For example, if you want to have `bbswitch` disable the card
-immediately when loading the module while disabling the card on unload, load the
+immediately when loading the module while enabling the card on unload, load the
 module with:
 
     # modprobe bbswitch load_state=0 unload_state=1

bbswitch.c

@@ -16,7 +16,7 @@
 #include <linux/suspend.h>
 #include <linux/seq_file.h>
 
-#define BBSWITCH_VERSION "0.4.1"
+#define BBSWITCH_VERSION "0.4.2"
 
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Toggle the discrete graphics card");
@@ -43,8 +43,6 @@ static const char acpi_optimus_dsm_muid[16] = {
     0xA7, 0x2B, 0x60, 0x42, 0xA6, 0xB5, 0xBE, 0xE0,
 };
 
-#define MXM_WMMX_GUID "F6CB5C3C-9CAE-4EBD-B577-931EA32A2CC0"
-#define MXM_WMMX_FUNC_DSM 0x4D53445F /* NVIDIA/Optimus DSM */
 static const char acpi_nvidia_dsm_muid[16] = {
     0xA0, 0xA0, 0x95, 0x9D, 0x60, 0x00, 0x48, 0x4D,
     0xB3, 0x4D, 0x7E, 0x5F, 0xEA, 0x12, 0x9F, 0xD4
@@ -60,23 +58,10 @@ It looks like something for Intel GPU:
 http://lxr.linux.no/#linux+v3.1.5/drivers/gpu/drm/i915/intel_acpi.c
  */
 
-struct mxdsm_args {
+#define DSM_TYPE_UNSUPPORTED    0
-    u32 func;
+#define DSM_TYPE_OPTIMUS        1
-    char muid[16];
+#define DSM_TYPE_NVIDIA         2
-    u32 revid;
+static int dsm_type = DSM_TYPE_UNSUPPORTED;
-    u32 sfnc;
-    char args[4];
-};
-
-enum dsm_type {
-    DSM_TYPE_UNSUPPORTED,
-    DSM_TYPE_OPTIMUS,
-    DSM_TYPE_NVIDIA,
-    /* _DSM call through a WMI MX method */
-    DSM_TYPE_OPTIMUS_WMI,
-    DSM_TYPE_NVIDIA_WMI,
-};
-static enum dsm_type dsm_type = DSM_TYPE_UNSUPPORTED;
 
 static struct pci_dev *dis_dev;
 static acpi_handle dis_handle;
@@ -86,17 +71,14 @@ static struct notifier_block nb;
 /* whether the card was off before suspend or not; on: 0, off: 1 */
 int dis_before_suspend_disabled;
 
-static char *buffer_to_string(const char buffer[], char *target) {
+static char *buffer_to_string(const char *buffer, size_t n, char *target) {
     int i;
-    for (i=0; i<sizeof(buffer); i++) {
+    for (i=0; i<n; i++) {
-        sprintf(target + i * 5, "%02X,", buffer[i]);
+        snprintf(target + i * 5, 5 * (n - i), "0x%02X,", buffer ? buffer[i] & 0xFF : 0);
     }
-    target[sizeof(buffer) * 5] = '\0';
     return target;
 }
 
-static int parse_dsm_result(struct acpi_buffer *output, uint32_t *result);
-
 // Returns 0 if the call succeeded and non-zero otherwise. If the call
 // succeeded, the result is stored in "result" providing that the result is an
 // integer or a buffer containing 4 values
@@ -105,6 +87,7 @@ static int acpi_call_dsm(acpi_handle handle, const char muid[16], int revid,
     struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
     struct acpi_object_list input;
     union acpi_object params[4];
+    union acpi_object *obj;
     int err;
 
     input.count = 4;
@@ -128,20 +111,17 @@ static int acpi_call_dsm(acpi_handle handle, const char muid[16], int revid,
 
     err = acpi_evaluate_object(handle, "_DSM", &input, &output);
     if (err) {
-        char tmp[5 * max(sizeof(muid), sizeof(args))];
+        char muid_str[5 * 16];
+        char args_str[5 * 4];
 
-        printk(KERN_WARNING "bbswitch: failed to evaluate _DSM {%s} %X %X"
+        printk(KERN_WARNING "bbswitch: failed to evaluate _DSM {%s} 0x%X 0x%X"
             " {%s}: %s\n",
-            buffer_to_string(muid, tmp), revid, func,
+            buffer_to_string(muid, 16, muid_str), revid, func,
-            buffer_to_string(args, tmp), acpi_format_exception(err));
+            buffer_to_string(args,  4, args_str), acpi_format_exception(err));
         return err;
     }
-    return parse_dsm_result(&output, result);
-}
 
-// Processes the result of an ACPI _DSM call and deallocates the result memory
+    obj = (union acpi_object *)output.pointer;
-static int parse_dsm_result(struct acpi_buffer *output, uint32_t *result) {
-    union acpi_object *obj = output->pointer;
 
     if (obj->type == ACPI_TYPE_INTEGER && result) {
         *result = obj->integer.value;
@@ -158,7 +138,7 @@ static int parse_dsm_result(struct acpi_buffer *output, uint32_t *result) {
             " type: %X\n", obj->type);
     }
 
-    kfree(output->pointer);
+    kfree(output.pointer);
     return 0;
 }
 
@@ -175,55 +155,11 @@ static int has_dsm_func(const char muid[16], int revid, int sfnc) {
     return result & 1 && result & (1 << sfnc);
 }
 
-// Returns 0 if the call succeeded and non-zero otherwise. If the call
-// succeeded, the result is stored in "result" providing that the result is an
-// integer or a buffer containing 4 values
-static int wmmx_call(const char muid[16], int revid, int func, char args[4],
-    uint32_t *result) {
-    struct mxdsm_args mx_args = {
-        .func = MXM_WMMX_FUNC_DSM,
-        .revid = revid,
-        .sfnc = func,
-    };
-    struct acpi_buffer input = { (acpi_size)sizeof(mx_args), &mx_args };
-    struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
-    acpi_status status;
-
-    memcpy(mx_args.muid, muid, sizeof(mx_args.muid));
-    if (args) {
-        memcpy(mx_args.args, args, sizeof(mx_args.args));
-    } else {
-        // some implementations do not like empty values
-        memset(mx_args.args, 0, sizeof(mx_args.args));
-    }
-
-    // 1, > 1 <-- required by at least Acer Travelmate 8472TG, seen on others
-    status = wmi_evaluate_method(MXM_WMMX_GUID, 1, 1, &input, &output);
-    if (ACPI_FAILURE(status)) {
-        printk(KERN_WARNING "bbswitch: failed to evaluate WMMX: %s\n",
-            acpi_format_exception(status));
-        return status;
-    }
-    return parse_dsm_result(&output, result);
-}
-
-// Returns 1 if a _DSM function and its function index exists and 0 otherwise
-static int has_wmi_func(const char muid[16], int revid, int sfnc) {
-    u32 result = 0;
-
-    // fail if the _DSM call failed
-    if (wmmx_call(muid, revid, 0, 0, &result))
-        return 0;
-
-    // ACPI Spec v4 9.14.1: if bit 0 is zero, no function is supported. If
-    // the n-th bit is enabled, function n is supported
-    return result & 1 && result & (1 << sfnc);
-}
-
 static int bbswitch_optimus_dsm(void) {
+    if (dsm_type == DSM_TYPE_OPTIMUS) {
         char args[] = {1, 0, 0, 3};
         u32 result = 0;
-    if (dsm_type == DSM_TYPE_OPTIMUS) {
+
         if (acpi_call_dsm(dis_handle, acpi_optimus_dsm_muid, 0x100, 0x1A, args,
             &result)) {
             // failure
@@ -231,21 +167,15 @@ static int bbswitch_optimus_dsm(void) {
         }
         printk(KERN_DEBUG "bbswitch: Result of Optimus _DSM call: %08X\n",
             result);
-    } else if (dsm_type == DSM_TYPE_OPTIMUS_WMI) {
-        if (wmmx_call(acpi_optimus_dsm_muid, 0x100, 0x1A, args, &result)) {
-            // failure
-            return 1;
-        }
-        printk(KERN_DEBUG "bbswitch: Result of WMMX call for Optimus: %08X\n",
-            result);
     }
     return 0;
 }
 
 static int bbswitch_acpi_off(void) {
+    if (dsm_type == DSM_TYPE_NVIDIA) {
         char args[] = {2, 0, 0, 0};
         u32 result = 0;
-    if (dsm_type == DSM_TYPE_NVIDIA) {
+
         if (acpi_call_dsm(dis_handle, acpi_nvidia_dsm_muid, 0x102, 0x3, args,
             &result)) {
             // failure
@@ -253,21 +183,15 @@ static int bbswitch_acpi_off(void) {
         }
         printk(KERN_DEBUG "bbswitch: Result of _DSM call for OFF: %08X\n",
             result);
-    } else if (dsm_type == DSM_TYPE_NVIDIA_WMI) {
-        if (wmmx_call(acpi_nvidia_dsm_muid, 0x102, 0x3, args, &result)) {
-            // failure
-            return 1;
-        }
-        printk(KERN_DEBUG "bbswitch: Result of WMMX call for OFF: %08X\n",
-            result);
     }
     return 0;
 }
 
 static int bbswitch_acpi_on(void) {
+    if (dsm_type == DSM_TYPE_NVIDIA) {
         char args[] = {1, 0, 0, 0};
         u32 result = 0;
-    if (dsm_type == DSM_TYPE_NVIDIA) {
+
         if (acpi_call_dsm(dis_handle, acpi_nvidia_dsm_muid, 0x102, 0x3, args,
             &result)) {
             // failure
@@ -275,13 +199,6 @@ static int bbswitch_acpi_on(void) {
         }
         printk(KERN_DEBUG "bbswitch: Result of _DSM call for ON: %08X\n",
             result);
-    } else if (dsm_type == DSM_TYPE_NVIDIA_WMI) {
-        if (wmmx_call(acpi_nvidia_dsm_muid, 0x102, 0x3, args, &result)) {
-            // failure
-            return 1;
-        }
-        printk(KERN_DEBUG "bbswitch: Result of WMMX call for ON: %08X\n",
-            result);
     }
     return 0;
 }
@@ -453,20 +370,10 @@ static int __init bbswitch_init(void) {
         return -ENODEV;
     }
 
-    if (has_wmi_func(acpi_optimus_dsm_muid, 0x100, 0x1A)) {
+    if (has_dsm_func(acpi_optimus_dsm_muid, 0x100, 0x1A)) {
-        dsm_type = DSM_TYPE_OPTIMUS_WMI;
-        printk(KERN_INFO "bbswitch: detected an Optimus WMMX function\n");
-    } else if (has_wmi_func(acpi_nvidia_dsm_muid, 0x102, 0x3)) {
-        dsm_type = DSM_TYPE_NVIDIA_WMI;
-        printk(KERN_INFO "bbswitch: detected a nVidia WMMX function\n");
-    } else if (has_dsm_func(acpi_optimus_dsm_muid, 0x100, 0x1A)) {
-        /* necessary for at least Lenovo Ideapad Z570 which does not have the
-         * WMMX method */
         dsm_type = DSM_TYPE_OPTIMUS;
         printk(KERN_INFO "bbswitch: detected an Optimus _DSM function\n");
     } else if (has_dsm_func(acpi_nvidia_dsm_muid, 0x102, 0x3)) {
-        /* necessary for at least Dell XPS L501X bios A08 which does not have
-         * the WMMX method */
         dsm_type = DSM_TYPE_NVIDIA;
         printk(KERN_INFO "bbswitch: detected a nVidia _DSM function\n");
     } else {