Patched to work on newer systems and added sanity check on input args

Author: johalun

intel_backlight.c

@@ -29,8 +29,11 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#include <errno.h>
+#include <limits.h>
 
 #include "intel_gpu_tools.h"
+
 #define NUM_ELEMENTS(array) (sizeof(array) / sizeof(array[0]))
 
 /* XXX PCH only today */
@@ -44,7 +47,7 @@ static void reg_write(uint32_t reg, uint32_t val)
 {
 	*(volatile uint32_t *)((volatile char*)mmio + reg) = val;
 }
-								  
+
 static int brightness_levels[] = {1, 2, 4, 6, 9, 12, 16, 20, 25, 30, 36, 43,
 								  51, 60, 70, 80, 90, 100};
 
@@ -66,33 +69,69 @@ static int brightness_decr(int curr)
 	return brightness_levels[i];
 }
 
+void print_usage() {
+	printf("Usage: intel_backlight [incr|decr|n] where n is brightness in percent\n");
+}
+
 int main(int argc, char** argv)
 {
 	uint32_t current, max, min;
+	uint32_t currentReg, maxReg;
 	int result;
 
 	intel_get_mmio(intel_get_pci_device());
 
 	current = reg_read(BLC_PWM_CPU_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
 	max = reg_read(BLC_PWM_PCH_CTL2) >> 16;
 
+	intel_check_pch();
+
+	switch( pch )
+	{
+	case PCH_LPT:
+	case PCH_SPT:
+	case PCH_KBP:
+		currentReg = 0xc8254;
+		maxReg = 0xc8254;
+		break;
+
+	default:
+		currentReg = BLC_PWM_CPU_CTL;
+		maxReg = BLC_PWM_PCH_CTL2;
+		break;
+	}
+
+	current = reg_read(currentReg) & BACKLIGHT_DUTY_CYCLE_MASK;
+	max = reg_read(maxReg) >> 16;
+
 	min = 0.5 + 0.5 * max / 100.0;	// 0.5%
 	/*
-	printf ("min: %d, NUM_ELEMENTS(brightness_levels): %d\n", min, 
+	printf ("min: %d, NUM_ELEMENTS(brightness_levels): %d\n", min,
 		NUM_ELEMENTS(brightness_levels));
 	*/
 	result = 0.5 + current * 100.0 / max;
-	printf ("current backlight value: %d%% (%d/%d)\n", result, current, max);
-	
+	printf ("Current backlight value: %d%% (%d/%d)\n", result, current, max);
+
 	if (argc > 1) {
 		uint32_t v;
-		if (0 == strcmp(argv[1], "incr")) 
+		if (0 == strcmp(argv[1], "incr"))
 			v = 0.5 + brightness_incr(result) * max / 100.0;
 		else if (0 == strcmp(argv[1], "decr"))
 			v = 0.5 + brightness_decr(result) * max / 100.0;
-		else	
-			v = 0.5 + atoi (argv[1]) * max / 100.0;
-		/*
+		else {
+			errno = 0;
+			char *endptr;
+			long val = strtol(argv[1], &endptr, 10);
+
+			if((errno == ERANGE && (val == LONG_MAX || val == LONG_MIN))
+			   || (errno != 0 && val == 0) || endptr == argv[1]) {
+				print_usage();
+				return result;
+			}
+
+			v = 0.5 + val * max / 100.0;
+		}
+	    /*
 		printf("v: %d\n", v);
 		*/
 		if (v < min)
@@ -102,10 +141,12 @@ int main(int argc, char** argv)
 		reg_write(BLC_PWM_CPU_CTL,
 			  (reg_read(BLC_PWM_CPU_CTL) &~ BACKLIGHT_DUTY_CYCLE_MASK) | v);
 		(void) reg_read(BLC_PWM_CPU_CTL);
+
+		reg_write(currentReg,
+				  (reg_read(currentReg) &~ BACKLIGHT_DUTY_CYCLE_MASK) | v);
+		(void) reg_read(currentReg);
 		result = 0.5 + v * 100.0 / max;
 		printf ("set backlight to %d%% (%d/%d)\n", result, v, max);
 	}
-
 	return result;
 }
-

intel_gpu_tools.h

@@ -103,6 +103,8 @@ enum pch_type {
 	PCH_IBX,
 	PCH_CPT,
 	PCH_LPT,
+	PCH_SPT,
+	PCH_KBP,
 };
 
 extern enum pch_type pch;

intel_pci.c

@@ -115,9 +115,15 @@ intel_check_pch(void)
 	case 0x9c00:
 		pch = PCH_LPT;
 		break;
+	case 0xA100:
+	case 0x9D00:
+		pch = PCH_SPT;
+		break;
+	case 0xA200:
+		pch = PCH_KBP;
+		break;
 	default:
 		pch = PCH_NONE;
 		return;
 	}
 }
-