支持设备树设置gpu显存大小以及buffer帧数，提高UI刷新帧率。

buildroot-external/board/arkmicro/ark1668e_devb/rootfs_overlay/etc/init.d/S04qtlaunch

@@ -4,12 +4,13 @@ export QT_QPA_FONTDIR=$QTDIR/lib/qt/fonts
 export QT_QPA_PLATFORM=eglfs
 export QT_QPA_EGLFS_INTEGRATION=eglfs_mali
 export QT_QPA_EGLFS_DEBUG=1
-export QT_QPA_EGLFS_FORCEVSYNC=1
+#export QT_QPA_EGLFS_FORCEVSYNC=1
 #export QT_QPA_EGLFS_FORCE888=1
 export QT_QPA_PLATFORM_PLUGIN_PATH=$QTDIR/lib/qt/plugins
 export QT_QPA_GENERIC_PLUGINS=evdevtouch:/dev/input/event0
 export LD_LIBRARY_PATH=$QTDIR/lib:$LD_LIBRARY_PATH
 export MALI_NOCLEAR=1
+export MALI_MAX_WINDOW_BUFFERS=3
 
 start() {
 	eval `dbus-launch --auto-syntax`

linux/arch/arm/boot/dts/ark1668e.dtsi

@@ -961,7 +961,7 @@
 			status = "disabled";
 		};
 
-		gpu@e9000000 {
+		gpu: gpu@e9000000 {
 			compatible = "arm,mali-400", "arm,mali-utgard";
 			reg = <0xe9000000 0x30000
 #ifdef DDR512

linux/arch/arm/boot/dts/ark1668e_devb.dts

@@ -199,6 +199,7 @@
 		lvds-con = <0x4545>;
 		lvds-con2 = <0xfa200141>;
 		bits-per-pixel = <32>;
+		fb-buffer-nums = <3>;
 		power-control-gpio = <&gportd 0 GPIO_ACTIVE_HIGH>;
 		lcd-wiring-mode = "RGB";
 		lcdcon-backlight;
@@ -419,3 +420,7 @@
 &can1{
 	status = "disabled";
 };
+
+&gpu {
+	shared-mem-size = <0x8000000>;
+};

linux/arch/arm/boot/dts/ark1668e_devb_emmc.dts

@@ -185,6 +185,7 @@
 		lvds-con = <0x4545>;
 		lvds-con2 = <0xfa200141>;
 		bits-per-pixel = <32>;
+		fb-buffer-nums = <3>;
 		power-control-gpio = <&gportd 0 GPIO_ACTIVE_HIGH>;
 		lcd-wiring-mode = "RGB";
 		lcdcon-backlight;
@@ -403,3 +404,7 @@
 &can1{
 	status = "disabled";
 };
+
+&gpu {
+	shared-mem-size = <0x8000000>;
+};

linux/drivers/gpu/arm/mali/platform/arm/arm.c

@@ -25,6 +25,7 @@
 #include "mali_kernel_common.h"
 #include <linux/dma-mapping.h>
 #include <linux/moduleparam.h>
+#include <linux/of.h>
 
 #include "arm_core_scaling.h"
 #include "mali_pp_scheduler.h"
@@ -191,6 +192,7 @@ int mali_platform_device_init(struct platform_device *device)
 	u32 m400_gp_version;
 #endif
 	struct resource *map = NULL;
+	u32 shared_mem_size = 0;
 
 	/* Detect present Mali GPU and connect the correct resources to the device */
 #if defined(CONFIG_ARCH_VEXPRESS)
@@ -268,6 +270,11 @@ int mali_platform_device_init(struct platform_device *device)
 		mali_gpu_data.fb_start = map->start;
 		mali_gpu_data.fb_size = resource_size(map);	
 	}
+
+	if(!of_property_read_u32(device->dev.of_node, "shared-mem-size", &shared_mem_size)) {
+	    mali_gpu_data.shared_mem_size = shared_mem_size;
+	}
+
 	err = platform_device_add_data(device, &mali_gpu_data, sizeof(mali_gpu_data));
 
 	if (0 == err) {

linux/drivers/video/fbdev/arkmicro/ark1668e_lcdc.h

@@ -95,6 +95,7 @@ struct ark1668e_lcdfb_pdata {
 	struct timer_list	backlight_timer;
     int	backlight_value;
 	int	backlight_delay;
+	int fb_buffer_nums;
 	void (*ark1668e_lcdfb_power_control)(struct ark1668e_lcdfb_pdata *pdata, int on);
 	struct list_head	pwr_gpios;
 };

linux/drivers/video/fbdev/arkmicro/ark1668e_lcdfb.c

@@ -260,8 +260,8 @@ static int ark1668e_lcdfb_check_var(struct fb_var_screeninfo *var,
 			     struct fb_info *info)
 {
 	struct device *dev = info->device;
-	/* struct ark1668e_lcdfb_info *sinfo = info->par;
-	struct ark1668e_lcdfb_pdata *pdata = &sinfo->pdata; */
+	struct ark1668e_lcdfb_info *sinfo = info->par;
+	struct ark1668e_lcdfb_pdata *pdata = &sinfo->pdata;
 
 	dev_dbg(dev, "%s:\n", __func__);
 
@@ -281,8 +281,12 @@ static int ark1668e_lcdfb_check_var(struct fb_var_screeninfo *var,
 	if (var->xres >= var->xres_virtual)
 		var->xres_virtual = var->xres;
 
-	if (var->yres >= var->yres_virtual)
-		var->yres_virtual = var->yres * 3;
+	if (var->yres >= var->yres_virtual) {
+		if (pdata->fb_buffer_nums > 0)
+			var->yres_virtual = var->yres * pdata->fb_buffer_nums;
+		else
+			var->yres_virtual = var->yres * 3;
+	}
 
 	/* Force same alignment for each line */
 	var->xres = (var->xres + 3) & ~3UL;
@@ -379,7 +383,7 @@ static int ark1668e_lcdfb_pan_display(struct fb_var_screeninfo *var,
 	addr = fix->smem_start + var->yoffset * fix->line_length
 		+ var->xoffset * info->var.bits_per_pixel / 8;
 
-	lcdc_writel(sinfo, ARK1668E_LCDC_OSD2_ADDR, addr);
+	sinfo->render_addr[ARK1668E_LCDC_LAYER_OSD2].yaddr = addr;
 
 	//printk(KERN_ALERT "ark1668e_lcdfb_pan_display 0x%x.\n", addr);
 
@@ -626,6 +630,8 @@ static int ark1668e_lcdfb_of_init(struct ark1668e_lcdfb_info *sinfo)
 		goto put_display_node;
 	}
 
+	ret = of_property_read_u32(display_np, "fb-buffer-nums", &pdata->fb_buffer_nums);
+
 	INIT_LIST_HEAD(&pdata->pwr_gpios);
 	ret = -ENOMEM;
 	for (i = 0; i < of_gpio_named_count(display_np, "power-control-gpio"); i++) {