[C++知识库]mtk6761 android9 点CMD屏开机瞬间屏出现雪花

以前点屏的时候遇到个问题，开机的瞬间显示屏会出现持续大概一秒钟的雪花。当时想的解决方法是在屏驱动中初始化函数里，先加载显示屏初始化参数，然后加个延迟函数，再将背光IC的使能脚拉高，当时验证无效。后来改了另一个文件mt_leds.c才解决出现雪花的这个问题，修改如下：
(背光IC的使能脚默认拉低）

+++ b/vendor/mediatek/proprietary/bootable/bootloader/lk/platform/mt6761/mt_leds.c
@@ -48,6 +48,9 @@
 #include <platform/mt6370_pmu_bled.h>
 #endif /* MTK_MT6370_PMU_BLED_SUPPORT */

+#define LCD_BL_EN (GPIO43 | 0x80000000)
+
+
 #define LEDS_PMIC_CONTROL_ENABLE   0
 struct cust_mt65xx_led *get_cust_led_dtsi(void);
 struct cust_mt65xx_led pled_dtsi[MT65XX_LED_TYPE_TOTAL];
@@ -433,15 +436,21 @@ void leds_deinit(void)

 void mt65xx_backlight_on(void)
 {
-       enum led_brightness backlight_level = get_cust_led_default_level();
-       LEDS_INFO("[LEDS]LK: mt65xx_backlight_on:level =  %d\n\r",backlight_level);
-       mt65xx_leds_brightness_set(MT65XX_LED_TYPE_LCD, backlight_level);
+       //enum led_brightness backlight_level = get_cust_led_default_level();
+       //LEDS_INFO("[LEDS]LK: mt65xx_backlight_on:level =  %d\n\r",backlight_level);
+       //mt65xx_leds_brightness_set(MT65XX_LED_TYPE_LCD, backlight_level);
+       mt_set_gpio_mode(LCD_BL_EN, GPIO_MODE_00);
+       mt_set_gpio_dir(LCD_BL_EN,  GPIO_DIR_OUT);
+       mt_set_gpio_out(LCD_BL_EN,  GPIO_OUT_ONE);
 }

 void mt65xx_backlight_off(void)
 {
-       LEDS_INFO("[LEDS]LK: mt65xx_backlight_off \n\r");
-       mt65xx_leds_brightness_set(MT65XX_LED_TYPE_LCD, LED_OFF);
+       //LEDS_INFO("[LEDS]LK: mt65xx_backlight_off \n\r");
+       //mt65xx_leds_brightness_set(MT65XX_LED_TYPE_LCD, LED_OFF);
+       mt_set_gpio_mode(LCD_BL_EN, GPIO_MODE_00);
+       mt_set_gpio_dir(LCD_BL_EN,  GPIO_DIR_OUT);
+       mt_set_gpio_out(LCD_BL_EN,  GPIO_OUT_ZERO);
 }