minuitwrp/graphics_fbdev.cpp - android_bootable_recovery - Gitiles

 /*
  * Copyright (C) 2014 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>

 #include <fcntl.h>
 #include <stdio.h>

 #include <sys/cdefs.h>
 #include <sys/ioctl.h>
 #include <sys/mman.h>
 #include <sys/types.h>

 #include <linux/fb.h>
 #include <linux/kd.h>

 #include "minui.h"
 #include "graphics.h"
 #include <pixelflinger/pixelflinger.h>

 static GRSurface* fbdev_init(minui_backend*);
 static GRSurface* fbdev_flip(minui_backend*);
 static void fbdev_blank(minui_backend*, bool);
 static void fbdev_exit(minui_backend*);

 static GRSurface gr_framebuffer[2];
 static bool double_buffered;
 static GRSurface* gr_draw = NULL;
 static int displayed_buffer;

 static fb_var_screeninfo vi;
 static int fb_fd = -1;
 static __u32 smem_len;

 static minui_backend my_backend = {
     .init = fbdev_init,
     .flip = fbdev_flip,
     .blank = fbdev_blank,
     .exit = fbdev_exit,
 };

 minui_backend* open_fbdev() {
     return &my_backend;
 }

 static void fbdev_blank(minui_backend* backend __unused, bool blank)
 {
 #if defined(TW_NO_SCREEN_BLANK) && defined(TW_BRIGHTNESS_PATH) && defined(TW_MAX_BRIGHTNESS)
     int fd;
     char brightness[4];
     snprintf(brightness, 4, "%03d", TW_MAX_BRIGHTNESS/2);

     fd = open(TW_BRIGHTNESS_PATH, O_RDWR);
     if (fd < 0) {
         perror("cannot open LCD backlight");
         return;
     }
     write(fd, blank ? "000" : brightness, 3);
     close(fd);

 #ifdef TW_SECONDARY_BRIGHTNESS_PATH
     fd = open(TW_SECONDARY_BRIGHTNESS_PATH, O_RDWR);
     if (fd < 0) {
         perror("cannot open LCD backlight 2");
         return;
     }
     write(fd, blank ? "000" : brightness, 3);
     close(fd);
 #endif
 #else
 #ifndef TW_NO_SCREEN_BLANK
     int ret;

     ret = ioctl(fb_fd, FBIOBLANK, blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
     if (ret < 0)
         perror("ioctl(): blank");
 #endif
 #endif
 }

 static void set_displayed_framebuffer(unsigned n)
 {
     if (n > 1 || !double_buffered) return;

     vi.yres_virtual = gr_framebuffer[0].height * 2;
     vi.yoffset = n * gr_framebuffer[0].height;
     vi.bits_per_pixel = gr_framebuffer[0].pixel_bytes * 8;
     if (ioctl(fb_fd, FBIOPUT_VSCREENINFO, &vi) < 0) {
         perror("active fb swap failed");
 #ifdef TW_FBIOPAN
     } else {
         if (ioctl(fb_fd, FBIOPAN_DISPLAY, &vi) < 0) {
             perror("pan failed");
         }
 #endif
     }
     displayed_buffer = n;
 }

 static GRSurface* fbdev_init(minui_backend* backend) {
     int retry = 20;
     int fd = -1;
     while (fd == -1) {
         fd = open("/dev/graphics/fb0", O_RDWR);
         if (fd == -1) {
             if (--retry) {
                 // wait for init to create the device node
                 perror("cannot open fb0 (retrying)");
                 usleep(100000);
             } else {
                 perror("cannot open fb0 (giving up)");
                 return NULL;
             }
         }
     }

     if (ioctl(fd, FBIOGET_VSCREENINFO, &vi) < 0) {
         perror("failed to get fb0 info (FBIOGET_VSCREENINFO)");
         close(fd);
         return NULL;
     }

 #ifdef RECOVERY_FORCE_RGB_565
     // Changing fb_var_screeninfo can affect fb_fix_screeninfo,
     // so this needs done before querying for fi.
     printf("Forcing pixel format: RGB_565\n");
     vi.blue.offset    = 0;
     vi.green.offset   = 5;
     vi.red.offset     = 11;
     vi.blue.length    = 5;
     vi.green.length   = 6;
     vi.red.length     = 5;
     vi.blue.msb_right = 0;
     vi.green.msb_right = 0;
     vi.red.msb_right = 0;
     vi.transp.offset  = 0;
     vi.transp.length  = 0;
     vi.bits_per_pixel = 16;

     if (ioctl(fd, FBIOPUT_VSCREENINFO, &vi) < 0) {
         perror("failed to put force_rgb_565 fb0 info");
         close(fd);
         return NULL;
     }
 #endif

     fb_fix_screeninfo fi;
     if (ioctl(fd, FBIOGET_FSCREENINFO, &fi) < 0) {
         perror("failed to get fb0 info (FBIOGET_FSCREENINFO)");
         close(fd);
         return NULL;
     }

     // We print this out for informational purposes only, but
     // throughout we assume that the framebuffer device uses an RGBX
     // pixel format.  This is the case for every development device I
     // have access to.  For some of those devices (eg, hammerhead aka
     // Nexus 5), FBIOGET_VSCREENINFO *reports* that it wants a
     // different format (XBGR) but actually produces the correct
     // results on the display when you write RGBX.
     //
     // If you have a device that actually *needs* another pixel format
     // (ie, BGRX, or 565), patches welcome...

     printf("fb0 reports (possibly inaccurate):\n"
            "  vi.bits_per_pixel = %d\n"
            "  vi.red.offset   = %3d   .length = %3d\n"
            "  vi.green.offset = %3d   .length = %3d\n"
            "  vi.blue.offset  = %3d   .length = %3d\n",
            vi.bits_per_pixel,
            vi.red.offset, vi.red.length,
            vi.green.offset, vi.green.length,
            vi.blue.offset, vi.blue.length);

     void* bits = mmap(0, fi.smem_len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
     if (bits == MAP_FAILED) {
         perror("failed to mmap framebuffer");
         close(fd);
         return NULL;
     }

     memset(bits, 0, fi.smem_len);

     gr_framebuffer[0].width = vi.xres;
     gr_framebuffer[0].height = vi.yres;
     gr_framebuffer[0].row_bytes = fi.line_length;
     gr_framebuffer[0].pixel_bytes = vi.bits_per_pixel / 8;
 #ifdef RECOVERY_GRAPHICS_FORCE_USE_LINELENGTH
     printf("Forcing line length\n");
     vi.xres_virtual = fi.line_length / gr_framebuffer[0].pixel_bytes;
 #endif
     gr_framebuffer[0].data = reinterpret_cast<uint8_t*>(bits);
     if (vi.bits_per_pixel == 16) {
         printf("setting GGL_PIXEL_FORMAT_RGB_565\n");
         gr_framebuffer[0].format = GGL_PIXEL_FORMAT_RGB_565;
     } else if (vi.red.offset == 8 || vi.red.offset == 16) {
         printf("setting GGL_PIXEL_FORMAT_BGRA_8888\n");
         gr_framebuffer[0].format = GGL_PIXEL_FORMAT_BGRA_8888;
     } else if (vi.red.offset == 0) {
         printf("setting GGL_PIXEL_FORMAT_RGBA_8888\n");
         gr_framebuffer[0].format = GGL_PIXEL_FORMAT_RGBA_8888;
     } else if (vi.red.offset == 24) {
         printf("setting GGL_PIXEL_FORMAT_RGBX_8888\n");
         gr_framebuffer[0].format = GGL_PIXEL_FORMAT_RGBX_8888;
     } else {
         if (vi.red.length == 8) {
             printf("No valid pixel format detected, trying GGL_PIXEL_FORMAT_RGBX_8888\n");
             gr_framebuffer[0].format = GGL_PIXEL_FORMAT_RGBX_8888;
         } else {
             printf("No valid pixel format detected, trying GGL_PIXEL_FORMAT_RGB_565\n");
             gr_framebuffer[0].format = GGL_PIXEL_FORMAT_RGB_565;
         }
     }

     // Drawing directly to the framebuffer takes about 5 times longer.
     // Instead, we will allocate some memory and draw to that, then
     // memcpy the data into the framebuffer later.
     gr_draw = (GRSurface*) malloc(sizeof(GRSurface));
     if (!gr_draw) {
         perror("failed to allocate gr_draw");
         close(fd);
         munmap(bits, fi.smem_len);
         return NULL;
     }
     memcpy(gr_draw, gr_framebuffer, sizeof(GRSurface));
     gr_draw->data = (unsigned char*) calloc(gr_draw->height * gr_draw->row_bytes, 1);
     if (!gr_draw->data) {
         perror("failed to allocate in-memory surface");
         close(fd);
         free(gr_draw);
         munmap(bits, fi.smem_len);
         return NULL;
     }

     /* check if we can use double buffering */
 #ifndef RECOVERY_GRAPHICS_FORCE_SINGLE_BUFFER
     if (vi.yres * fi.line_length * 2 <= fi.smem_len) {
         double_buffered = true;
         printf("double buffered\n");

         memcpy(gr_framebuffer+1, gr_framebuffer, sizeof(GRSurface));
         gr_framebuffer[1].data = gr_framebuffer[0].data +
             gr_framebuffer[0].height * gr_framebuffer[0].row_bytes;

     } else {
 #else
     {
         printf("RECOVERY_GRAPHICS_FORCE_SINGLE_BUFFER := true\n");
 #endif
         double_buffered = false;
         printf("single buffered\n");
     }
 #if defined(RECOVERY_BGRA)
     printf("RECOVERY_BGRA\n");
 #endif
     fb_fd = fd;
     set_displayed_framebuffer(0);

     printf("framebuffer: %d (%d x %d)\n", fb_fd, gr_draw->width, gr_draw->height);

     fbdev_blank(backend, true);
     fbdev_blank(backend, false);

     smem_len = fi.smem_len;

     return gr_draw;
 }

 static GRSurface* fbdev_flip(minui_backend* backend __unused) {
 #if defined(RECOVERY_BGRA)
     // In case of BGRA, do some byte swapping
     unsigned char* ucfb_vaddr = (unsigned char*)gr_draw->data;
     for (int idx = 0 ; idx < (gr_draw->height * gr_draw->row_bytes);
             idx += 4) {
         unsigned char tmp = ucfb_vaddr[idx];
         ucfb_vaddr[idx    ] = ucfb_vaddr[idx + 2];
         ucfb_vaddr[idx + 2] = tmp;
     }
 #endif
 #ifndef BOARD_HAS_FLIPPED_SCREEN
     if (double_buffered) {
         // Copy from the in-memory surface to the framebuffer.
         memcpy(gr_framebuffer[1-displayed_buffer].data, gr_draw->data,
                gr_draw->height * gr_draw->row_bytes);
         set_displayed_framebuffer(1-displayed_buffer);
     } else {
         // Copy from the in-memory surface to the framebuffer.
         memcpy(gr_framebuffer[0].data, gr_draw->data,
                gr_draw->height * gr_draw->row_bytes);
     }
 #else
     int gr_active_fb = 0;
     if (double_buffered)
         gr_active_fb = 1-displayed_buffer;

     /* flip buffer 180 degrees for devices with physically inverted screens */
     unsigned int row_pixels = gr_draw->row_bytes / gr_framebuffer[0].pixel_bytes;
     if (gr_framebuffer[0].pixel_bytes == 4) {
         for (unsigned int y = 0; y < gr_draw->height; ++y) {
             uint32_t* dst = reinterpret_cast<uint32_t*>(gr_framebuffer[gr_active_fb].data) + y * row_pixels;
             uint32_t* src = reinterpret_cast<uint32_t*>(gr_draw->data) + (gr_draw->height - y - 1) * row_pixels + gr_draw->width;
             for (unsigned int x = 0; x < gr_draw->width; ++x)
                 *(dst++) = *(--src);
         }
     } else {
         for (unsigned int y = 0; y < gr_draw->height; ++y) {
             uint16_t* dst = reinterpret_cast<uint16_t*>(gr_framebuffer[gr_active_fb].data) + y * row_pixels;
             uint16_t* src = reinterpret_cast<uint16_t*>(gr_draw->data) + (gr_draw->height - y - 1) * row_pixels + gr_draw->width;
             for (unsigned int x = 0; x < gr_draw->width; ++x)
                  *(dst++) = *(--src);
         }
     }

     if (double_buffered)
         set_displayed_framebuffer(1-displayed_buffer);
 #endif
     return gr_draw;
 }

 static void fbdev_exit(minui_backend* backend __unused) {
     close(fb_fd);
     fb_fd = -1;

     if (gr_draw) {
         free(gr_draw->data);
         free(gr_draw);
     }
     gr_draw = NULL;
     munmap(gr_framebuffer[0].data, smem_len);
 }
	/*
	* Copyright (C) 2014 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include <stdbool.h>
	#include <stdlib.h>
	#include <string.h>
	#include <unistd.h>

	#include <fcntl.h>
	#include <stdio.h>

	#include <sys/cdefs.h>
	#include <sys/ioctl.h>
	#include <sys/mman.h>
	#include <sys/types.h>

	#include <linux/fb.h>
	#include <linux/kd.h>

	#include "minui.h"
	#include "graphics.h"
	#include <pixelflinger/pixelflinger.h>

	static GRSurface* fbdev_init(minui_backend*);
	static GRSurface* fbdev_flip(minui_backend*);
	static void fbdev_blank(minui_backend*, bool);
	static void fbdev_exit(minui_backend*);

	static GRSurface gr_framebuffer[2];
	static bool double_buffered;
	static GRSurface* gr_draw = NULL;
	static int displayed_buffer;

	static fb_var_screeninfo vi;
	static int fb_fd = -1;
	static __u32 smem_len;

	static minui_backend my_backend = {
	.init = fbdev_init,
	.flip = fbdev_flip,
	.blank = fbdev_blank,
	.exit = fbdev_exit,
	};

	minui_backend* open_fbdev() {
	return &my_backend;
	}

	static void fbdev_blank(minui_backend* backend __unused, bool blank)
	{
	#if defined(TW_NO_SCREEN_BLANK) && defined(TW_BRIGHTNESS_PATH) && defined(TW_MAX_BRIGHTNESS)
	int fd;
	char brightness[4];
	snprintf(brightness, 4, "%03d", TW_MAX_BRIGHTNESS/2);

	fd = open(TW_BRIGHTNESS_PATH, O_RDWR);
	if (fd < 0) {
	perror("cannot open LCD backlight");
	return;
	}
	write(fd, blank ? "000" : brightness, 3);
	close(fd);

	#ifdef TW_SECONDARY_BRIGHTNESS_PATH
	fd = open(TW_SECONDARY_BRIGHTNESS_PATH, O_RDWR);
	if (fd < 0) {
	perror("cannot open LCD backlight 2");
	return;
	}
	write(fd, blank ? "000" : brightness, 3);
	close(fd);
	#endif
	#else
	#ifndef TW_NO_SCREEN_BLANK
	int ret;

	ret = ioctl(fb_fd, FBIOBLANK, blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
	if (ret < 0)
	perror("ioctl(): blank");
	#endif
	#endif
	}

	static void set_displayed_framebuffer(unsigned n)
	{
	if (n > 1 \|\| !double_buffered) return;

	vi.yres_virtual = gr_framebuffer[0].height * 2;
	vi.yoffset = n * gr_framebuffer[0].height;
	vi.bits_per_pixel = gr_framebuffer[0].pixel_bytes * 8;
	if (ioctl(fb_fd, FBIOPUT_VSCREENINFO, &vi) < 0) {
	perror("active fb swap failed");
	#ifdef TW_FBIOPAN
	} else {
	if (ioctl(fb_fd, FBIOPAN_DISPLAY, &vi) < 0) {
	perror("pan failed");
	}
	#endif
	}
	displayed_buffer = n;
	}

	static GRSurface* fbdev_init(minui_backend* backend) {
	int retry = 20;
	int fd = -1;
	while (fd == -1) {
	fd = open("/dev/graphics/fb0", O_RDWR);
	if (fd == -1) {
	if (--retry) {
	// wait for init to create the device node
	perror("cannot open fb0 (retrying)");
	usleep(100000);
	} else {
	perror("cannot open fb0 (giving up)");
	return NULL;
	}
	}
	}

	if (ioctl(fd, FBIOGET_VSCREENINFO, &vi) < 0) {
	perror("failed to get fb0 info (FBIOGET_VSCREENINFO)");
	close(fd);
	return NULL;
	}

	#ifdef RECOVERY_FORCE_RGB_565
	// Changing fb_var_screeninfo can affect fb_fix_screeninfo,
	// so this needs done before querying for fi.
	printf("Forcing pixel format: RGB_565\n");
	vi.blue.offset = 0;
	vi.green.offset = 5;
	vi.red.offset = 11;
	vi.blue.length = 5;
	vi.green.length = 6;
	vi.red.length = 5;
	vi.blue.msb_right = 0;
	vi.green.msb_right = 0;
	vi.red.msb_right = 0;
	vi.transp.offset = 0;
	vi.transp.length = 0;
	vi.bits_per_pixel = 16;

	if (ioctl(fd, FBIOPUT_VSCREENINFO, &vi) < 0) {
	perror("failed to put force_rgb_565 fb0 info");
	close(fd);
	return NULL;
	}
	#endif

	fb_fix_screeninfo fi;
	if (ioctl(fd, FBIOGET_FSCREENINFO, &fi) < 0) {
	perror("failed to get fb0 info (FBIOGET_FSCREENINFO)");
	close(fd);
	return NULL;
	}

	// We print this out for informational purposes only, but
	// throughout we assume that the framebuffer device uses an RGBX
	// pixel format. This is the case for every development device I
	// have access to. For some of those devices (eg, hammerhead aka
	// Nexus 5), FBIOGET_VSCREENINFO reports that it wants a
	// different format (XBGR) but actually produces the correct
	// results on the display when you write RGBX.
	//
	// If you have a device that actually needs another pixel format
	// (ie, BGRX, or 565), patches welcome...

	printf("fb0 reports (possibly inaccurate):\n"
	" vi.bits_per_pixel = %d\n"
	" vi.red.offset = %3d .length = %3d\n"
	" vi.green.offset = %3d .length = %3d\n"
	" vi.blue.offset = %3d .length = %3d\n",
	vi.bits_per_pixel,
	vi.red.offset, vi.red.length,
	vi.green.offset, vi.green.length,
	vi.blue.offset, vi.blue.length);

	void* bits = mmap(0, fi.smem_len, PROT_READ \| PROT_WRITE, MAP_SHARED, fd, 0);
	if (bits == MAP_FAILED) {
	perror("failed to mmap framebuffer");
	close(fd);
	return NULL;
	}

	memset(bits, 0, fi.smem_len);

	gr_framebuffer[0].width = vi.xres;
	gr_framebuffer[0].height = vi.yres;
	gr_framebuffer[0].row_bytes = fi.line_length;
	gr_framebuffer[0].pixel_bytes = vi.bits_per_pixel / 8;
	#ifdef RECOVERY_GRAPHICS_FORCE_USE_LINELENGTH
	printf("Forcing line length\n");
	vi.xres_virtual = fi.line_length / gr_framebuffer[0].pixel_bytes;
	#endif
	gr_framebuffer[0].data = reinterpret_cast<uint8_t*>(bits);
	if (vi.bits_per_pixel == 16) {
	printf("setting GGL_PIXEL_FORMAT_RGB_565\n");
	gr_framebuffer[0].format = GGL_PIXEL_FORMAT_RGB_565;
	} else if (vi.red.offset == 8 \|\| vi.red.offset == 16) {
	printf("setting GGL_PIXEL_FORMAT_BGRA_8888\n");
	gr_framebuffer[0].format = GGL_PIXEL_FORMAT_BGRA_8888;
	} else if (vi.red.offset == 0) {
	printf("setting GGL_PIXEL_FORMAT_RGBA_8888\n");
	gr_framebuffer[0].format = GGL_PIXEL_FORMAT_RGBA_8888;
	} else if (vi.red.offset == 24) {
	printf("setting GGL_PIXEL_FORMAT_RGBX_8888\n");
	gr_framebuffer[0].format = GGL_PIXEL_FORMAT_RGBX_8888;
	} else {
	if (vi.red.length == 8) {
	printf("No valid pixel format detected, trying GGL_PIXEL_FORMAT_RGBX_8888\n");
	gr_framebuffer[0].format = GGL_PIXEL_FORMAT_RGBX_8888;
	} else {
	printf("No valid pixel format detected, trying GGL_PIXEL_FORMAT_RGB_565\n");
	gr_framebuffer[0].format = GGL_PIXEL_FORMAT_RGB_565;
	}
	}

	// Drawing directly to the framebuffer takes about 5 times longer.
	// Instead, we will allocate some memory and draw to that, then
	// memcpy the data into the framebuffer later.
	gr_draw = (GRSurface*) malloc(sizeof(GRSurface));
	if (!gr_draw) {
	perror("failed to allocate gr_draw");
	close(fd);
	munmap(bits, fi.smem_len);
	return NULL;
	}
	memcpy(gr_draw, gr_framebuffer, sizeof(GRSurface));
	gr_draw->data = (unsigned char) calloc(gr_draw->height gr_draw->row_bytes, 1);
	if (!gr_draw->data) {
	perror("failed to allocate in-memory surface");
	close(fd);
	free(gr_draw);
	munmap(bits, fi.smem_len);
	return NULL;
	}

	/* check if we can use double buffering */
	#ifndef RECOVERY_GRAPHICS_FORCE_SINGLE_BUFFER
	if (vi.yres * fi.line_length * 2 <= fi.smem_len) {
	double_buffered = true;
	printf("double buffered\n");

	memcpy(gr_framebuffer+1, gr_framebuffer, sizeof(GRSurface));
	gr_framebuffer[1].data = gr_framebuffer[0].data +
	gr_framebuffer[0].height * gr_framebuffer[0].row_bytes;

	} else {
	#else
	{
	printf("RECOVERY_GRAPHICS_FORCE_SINGLE_BUFFER := true\n");
	#endif
	double_buffered = false;
	printf("single buffered\n");
	}
	#if defined(RECOVERY_BGRA)
	printf("RECOVERY_BGRA\n");
	#endif
	fb_fd = fd;
	set_displayed_framebuffer(0);

	printf("framebuffer: %d (%d x %d)\n", fb_fd, gr_draw->width, gr_draw->height);

	fbdev_blank(backend, true);
	fbdev_blank(backend, false);

	smem_len = fi.smem_len;

	return gr_draw;
	}

	static GRSurface* fbdev_flip(minui_backend* backend __unused) {
	#if defined(RECOVERY_BGRA)
	// In case of BGRA, do some byte swapping
	unsigned char* ucfb_vaddr = (unsigned char*)gr_draw->data;
	for (int idx = 0 ; idx < (gr_draw->height * gr_draw->row_bytes);
	idx += 4) {
	unsigned char tmp = ucfb_vaddr[idx];
	ucfb_vaddr[idx ] = ucfb_vaddr[idx + 2];
	ucfb_vaddr[idx + 2] = tmp;
	}
	#endif
	#ifndef BOARD_HAS_FLIPPED_SCREEN
	if (double_buffered) {
	// Copy from the in-memory surface to the framebuffer.
	memcpy(gr_framebuffer[1-displayed_buffer].data, gr_draw->data,
	gr_draw->height * gr_draw->row_bytes);
	set_displayed_framebuffer(1-displayed_buffer);
	} else {
	// Copy from the in-memory surface to the framebuffer.
	memcpy(gr_framebuffer[0].data, gr_draw->data,
	gr_draw->height * gr_draw->row_bytes);
	}
	#else
	int gr_active_fb = 0;
	if (double_buffered)
	gr_active_fb = 1-displayed_buffer;

	/* flip buffer 180 degrees for devices with physically inverted screens */
	unsigned int row_pixels = gr_draw->row_bytes / gr_framebuffer[0].pixel_bytes;
	if (gr_framebuffer[0].pixel_bytes == 4) {
	for (unsigned int y = 0; y < gr_draw->height; ++y) {
	uint32_t* dst = reinterpret_cast<uint32_t>(gr_framebuffer[gr_active_fb].data) + y row_pixels;
	uint32_t* src = reinterpret_cast<uint32_t>(gr_draw->data) + (gr_draw->height - y - 1) row_pixels + gr_draw->width;
	for (unsigned int x = 0; x < gr_draw->width; ++x)
	(dst++) = (--src);
	}
	} else {
	for (unsigned int y = 0; y < gr_draw->height; ++y) {
	uint16_t* dst = reinterpret_cast<uint16_t>(gr_framebuffer[gr_active_fb].data) + y row_pixels;
	uint16_t* src = reinterpret_cast<uint16_t>(gr_draw->data) + (gr_draw->height - y - 1) row_pixels + gr_draw->width;
	for (unsigned int x = 0; x < gr_draw->width; ++x)
	(dst++) = (--src);
	}
	}

	if (double_buffered)
	set_displayed_framebuffer(1-displayed_buffer);
	#endif
	return gr_draw;
	}

	static void fbdev_exit(minui_backend* backend __unused) {
	close(fb_fd);
	fb_fd = -1;

	if (gr_draw) {
	free(gr_draw->data);
	free(gr_draw);
	}
	gr_draw = NULL;
	munmap(gr_framebuffer[0].data, smem_len);
	}