Repository cleanup, added several methods and scripts from feedback

README → README.md

@@ -1,38 +1,45 @@
-A kernel module that enables you to call ACPI methods by writing the method
-name followed by arguments to /proc/acpi/call.
+A kernel simple module that enables you to call ACPI methods by writing the
+method name followed by arguments to `/proc/acpi/call`.
+
+This module is to be considered a proof-of-concept and has been superseeded by
+projects like [bbswitch](https://github.com/Bumblebee-Project/bbswitch). It
+allows you to tamper with your system and should be used with caution.
 
 Usage:
 
     echo '<call>' | sudo tee /proc/acpi/call
+
 You can then retrieve the result of the call by checking your dmesg or:
 
     sudo cat /proc/acpi/call
 
 An example to turn off discrete graphics card in a dual graphics environment
 (like NVIDIA Optimus):
 
-# turn off discrete graphics card
-echo '\_SB.PCI0.PEG1.GFX0.DOFF' > /proc/acpi/call
-# turn it back on
-echo '\_SB.PCI0.PEG1.GFX0.DON' > /proc/acpi/call
+    # turn off discrete graphics card
+    echo '\_SB.PCI0.PEG1.GFX0.DOFF' > /proc/acpi/call
+    # turn it back on
+    echo '\_SB.PCI0.PEG1.GFX0.DON' > /proc/acpi/call
 
 These work on my ASUS K52J notebook, but may not work for you. For a list of
 methods to try, see http://linux-hybrid-graphics.blogspot.com/ or try running
-the provided script test_off.sh
+the provided script `examples/turn_off_gpu.sh`
 
 It SHOULD be ok to test all of the methods, until you see a drop in battery
-drain rate (grep rate /proc/acpi/battery/BAT0/state), however it comes
-with NO WARRANTY.
+drain rate (`grep rate /proc/acpi/battery/BAT0/state`), however it comes
+with NO WARRANTY - it may hang your computer/laptop, fail to work, etc.
 
-You can pass parameters to acpi_call by writing them after the method,
+You can pass parameters to `acpi_call` by writing them after the method,
 separated by single space. Currently, you can pass the following parameter
 types:
+
 * ACPI_INTEGER - by writing NNN or 0xNNN, where NNN is an integer/hex
 * ACPI_STRING - by enclosing the string in quotes: "hello, world"
 * ACPI_BUFFER - by writing bXXXX, where XXXX is a hex string without spaces,
                 or by writing { b1, b2, b3, b4 }, where b1-4 are integers
 
-The status after a call can be read back from /proc/acpi/call:
+The status after a call can be read back from `/proc/acpi/call`:
+
 * 'not called' - nothing to report
 * 'Error: <description>' - the call failed
 * '0xNN' - the call succeeded, and returned an integer

acpi_call.c

@@ -9,7 +9,13 @@
 
 MODULE_LICENSE("GPL");
 
+/* Uncomment the following line to enable debug messages */
+/*
+#define DEBUG
+*/
+
 #define BUFFER_SIZE 256
+#define MAX_ACPI_ARGS 16
 
 extern struct proc_dir_entry *acpi_root_dir;
 
@@ -23,6 +29,7 @@ static size_t get_avail_bytes(void) {
 static char *get_buffer_end(void) {
     return result_buffer + strlen(result_buffer);
 }
+
 /** Appends the contents of an acpi_object to the result buffer
 @param result   An acpi object holding result data
 @returns        0 if the result could fully be saved, a higher value otherwise
@@ -87,7 +94,9 @@ static void do_acpi_call(const char * method, int argc, union acpi_object *argv)
     struct acpi_object_list arg;
     struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 
+#ifdef DEBUG
     printk(KERN_INFO "acpi_call: Calling %s\n", method);
+#endif
 
     // get the handle of the method, must be a fully qualified path
     status = acpi_get_handle(NULL, (acpi_string) method, &handle);
@@ -117,7 +126,9 @@ static void do_acpi_call(const char * method, int argc, union acpi_object *argv)
     acpi_result_to_string(buffer.pointer);
     kfree(buffer.pointer);
 
+#ifdef DEBUG
     printk(KERN_INFO "acpi_call: Call successful: %s\n", result_buffer);
+#endif
 }
 
 /** Decodes 2 hex characters to an u8 int
@@ -146,7 +157,7 @@ static char *parse_acpi_args(char *input, int *nargs, union acpi_object **args)
     if (*s == 0)
         return input;
 
-    *args = (union acpi_object *) kmalloc(16 * sizeof(union acpi_object), GFP_KERNEL);
+    *args = (union acpi_object *) kmalloc(MAX_ACPI_ARGS * sizeof(union acpi_object), GFP_KERNEL);
 
     while (*s) {
         if (*s == ' ') {
@@ -290,8 +301,11 @@ static int acpi_proc_read(char *page, char **start, off_t off,
         return 0;
     }
 
+    // output the current result buffer
     len = strlen(result_buffer);
     memcpy(page, result_buffer, len + 1);
+
+    // initialize the result buffer for later
     strcpy(result_buffer, "not called");
 
     return len;
@@ -311,15 +325,21 @@ static int __init init_acpi_call(void)
 
     acpi_entry->write_proc = acpi_proc_write;
     acpi_entry->read_proc = acpi_proc_read;
+
+#ifdef DEBUG
     printk(KERN_INFO "acpi_call: Module loaded successfully\n");
+#endif
 
     return 0;
 }
 
 static void __exit unload_acpi_call(void)
 {
     remove_proc_entry("call", acpi_root_dir);
+
+#ifdef DEBUG
     printk(KERN_INFO "acpi_call: Module unloaded successfully\n");
+#endif
 }
 
 module_init(init_acpi_call);

examples/dellL702X.sh

@@ -0,0 +1,46 @@
+#!/bin/sh
+# Power control for Dell L702X
+# by Jos Hickson
+# adapted from "Power control for Asus 1215N Optimus by Pete Eberlein"
+
+if ! lsmod | grep -q acpi_call; then
+    echo "Error: acpi_call module not loaded"
+    exit
+fi
+
+acpi_call () {
+    echo "$*" > /proc/acpi/call
+    cat /proc/acpi/call
+}
+
+
+case "$1" in
+off)
+    echo _DSM $(acpi_call "\_SB.PCI0.PEG0.PEGP._DSM" \
+	"{0xF8,0xD8,0x86,0xA4,0xDA,0x0B,0x1B,0x47," \
+	 "0xA7,0x2B,0x60,0x42,0xA6,0xB5,0xBE,0xE0}" \
+	 "0x100 0x1A {0x1,0x0,0x0,0x3}")
+	# ok to turn off: Buffer {0x59 0x0 0x0 0x11}
+	# is already off: Buffer {0x41 0x0 0x0 0x11}
+    echo _PS3 $(acpi_call "\_SB.PCI0.PEG0.PEGP._PS3")
+;;
+on)
+    echo _PS0 $(acpi_call "\_SB.PCI0.PEG0.PEGP._PS0")
+;;
+*)
+    echo "Usage: $0 [on|off]"
+esac
+
+
+PSC=$(acpi_call "\_SB.PCI0.PEG0.PEGP._PSC")
+#echo _PSC ${PSC}
+case "$PSC" in
+0x0)
+    PSC="on"
+;;
+0x3)
+    PSC="off"
+;;
+esac
+echo "Dell L702X Optimus appears to be ${PSC}"
+

test_off.sh → examples/turn_off_gpu.sh

@@ -27,23 +27,26 @@ methods="
 \_SB.PCI0.LPC.EC.PUBS._OFF
 \_SB.PCI0.P0P2.NVID._OFF
 \_SB.PCI0.P0P2.VGA.PX02
+\_SB_.PCI0.PEGP.DGFX._OFF
+\_SB_.PCI0.VGA.PX02
 "
 
-    for m in $methods; do
-echo -n "Trying $m: "
-        echo $m > /proc/acpi/call
-        result=$(cat /proc/acpi/call)
-        case "$result" in
+for m in $methods; do
+    echo -n "Trying $m: "
+    echo $m > /proc/acpi/call
+    result=$(cat /proc/acpi/call)
+    case "$result" in
         Error*)
             echo "failed"
         ;;
         *)
             echo "works!"
-            #break
+            # break # try out outher methods too
         ;;
-        esac
+    esac
 done
+
 else
-echo 'The acpi_call module is not loaded'
+    echo "The acpi_call module is not loaded, try running 'modprobe acpi_call' or 'insmod acpi_call.ko' as root"
     exit 1
 fi