refactor(core/embed): improve display driver init/deinit

[no changelog]

core/embed/boardloader/main.c

@@ -274,7 +274,8 @@ int main(void) {
   dma2d_init();
 #endif
 
-  display_init();
+  display_init(DISPLAY_RESET_CONTENT);
+
   display_clear();
   display_refresh();
 
@@ -324,6 +325,7 @@ int main(void) {
   // This includes the version of bootloader potentially updated from SD card.
   write_bootloader_min_version(hdr->monotonic);
 
+  display_deinit(DISPLAY_RETAIN_CONTENT);
   ensure_compatible_settings();
 
   mpu_config_off();

core/embed/bootloader/emulator.c

@@ -92,7 +92,7 @@ bool load_firmware(const char *filename, uint8_t *hash) {
 }
 
 __attribute__((noreturn)) int main(int argc, char **argv) {
-  display_init();
+  display_init(DISPLAY_RESET_CONTENT);
   flash_init();
   flash_otp_init();
 

core/embed/bootloader/main.c

@@ -330,7 +330,7 @@ void real_jump_to_firmware(void) {
     ui_screen_boot_stage_1(false);
   }
 
-  display_finish_actions();
+  display_deinit(DISPLAY_RETAIN_CONTENT);
   ensure_compatible_settings();
 
   mpu_config_off();
@@ -339,7 +339,6 @@ void real_jump_to_firmware(void) {
 
 #ifdef STM32U5
 __attribute__((noreturn)) void jump_to_fw_through_reset(void) {
-  display_finish_actions();
   display_fade(display_backlight(-1), 0, 200);
 
   disable_irq();
@@ -371,7 +370,7 @@ int bootloader_main(void) {
   i2c_init();
 #endif
 
-  display_reinit();
+  display_init(DISPLAY_RETAIN_CONTENT);
 
 #ifdef USE_DMA2D
   dma2d_init();

core/embed/firmware/main.c

@@ -155,7 +155,7 @@ int main(void) {
   dma2d_init();
 #endif
 
-  display_reinit();
+  display_init(DISPLAY_RETAIN_CONTENT);
 
 #ifdef STM32U5
   check_oem_keys();

core/embed/prodtest/main.c

@@ -777,8 +777,7 @@ void cpuid_read(void) {
 
 int main(void) {
   svc_init();
-  display_reinit();
-  display_orientation(0);
+  display_init(DISPLAY_RETAIN_CONTENT);
   random_delays_init();
 #ifdef STM32U5
   secure_aes_init();

core/embed/trezorhal/display.h

@@ -63,7 +63,7 @@ int display_orientation(int degrees);
 int display_get_orientation(void);
 int display_backlight(int val);
 
-void display_init(void);
+void display_init_all(void);
 void display_reinit(void);
 void display_sync(void);
 void display_refresh(void);
@@ -77,5 +77,24 @@ uint8_t *display_get_wr_addr(void);
 void display_shift_window(uint16_t pixels);
 uint16_t display_get_window_offset(void);
 
+typedef enum {
+  // Clear the display content
+  DISPLAY_RESET_CONTENT,
+  // Keeps the display without any changes
+  DISPLAY_RETAIN_CONTENT
+} display_content_mode_t;
+
+static inline void display_init(display_content_mode_t mode) {
+  if (mode == DISPLAY_RESET_CONTENT) {
+    display_init_all();
+  } else {
+    display_reinit();
+  }
+}
+
+static inline void display_deinit(display_content_mode_t mode) {
+  display_finish_actions();
+}
+
 #endif  // NEW_RENDERING
 #endif  // TREZORHAL_DISPLAY_H

core/embed/trezorhal/stm32f4/common.c

@@ -42,7 +42,7 @@ uint32_t systick_val_copy = 0;
 extern void shutdown_privileged(void);
 
 void __attribute__((noreturn)) trezor_shutdown(void) {
-  display_finish_actions();
+  display_deinit(DISPLAY_RETAIN_CONTENT);
 #ifdef USE_SVC_SHUTDOWN
   svc_shutdown();
 #else

core/embed/trezorhal/stm32f4/displays/ltdc.c

@@ -221,7 +221,7 @@ int display_backlight(int val) {
 
 void display_init_seq(void) { display_unsleep(); }
 
-void display_init(void) {
+void display_init_all(void) {
   GPIO_InitTypeDef GPIO_InitStructure = {0};
 
   /* Enable the LTDC and DMA2D Clock */

core/embed/trezorhal/stm32f4/displays/st7789v.c

@@ -389,7 +389,7 @@ void display_setup_te_interrupt(void) {
 }
 #endif
 
-void display_init(void) {
+void display_init_all(void) {
   // init peripherals
   __HAL_RCC_GPIOE_CLK_ENABLE();
   __HAL_RCC_GPIOA_CLK_ENABLE();

core/embed/trezorhal/stm32f4/displays/ug-2828tswig01.c

@@ -270,7 +270,7 @@ void display_init_seq(void) {
   display_unsleep();
 }
 
-void display_init(void) {
+void display_init_all(void) {
   // init peripherals
   __HAL_RCC_GPIOC_CLK_ENABLE();
   __HAL_RCC_GPIOD_CLK_ENABLE();

core/embed/trezorhal/stm32f4/displays/vg-2864ksweg01.c

@@ -153,7 +153,7 @@ void display_handle_init(void) {
   spi_handle.Init.Mode = SPI_MODE_MASTER;
 }
 
-void display_init(void) {
+void display_init_all(void) {
   OLED_DC_CLK_ENA();
   OLED_CS_CLK_ENA();
   OLED_RST_CLK_ENA();

core/embed/trezorhal/stm32f4/supervise.c

@@ -31,6 +31,8 @@ __attribute__((noreturn)) static void _reboot_to_bootloader(
 #else
 __attribute__((noreturn)) static void _reboot_to_bootloader(
     boot_command_t boot_command) {
+  display_deinit(DISPLAY_RETAIN_CONTENT);
+  ensure_compatible_settings();
   mpu_config_bootloader();
   jump_to_with_flag(IMAGE_CODE_ALIGN(BOOTLOADER_START + IMAGE_HEADER_SIZE),
                     boot_command);
@@ -40,14 +42,12 @@ __attribute__((noreturn)) static void _reboot_to_bootloader(
 #endif
 
 void svc_reboot_to_bootloader(void) {
-  display_finish_actions();
   boot_command_t boot_command = bootargs_get_command();
   if (is_mode_unprivileged() && !is_mode_handler()) {
     register uint32_t r0 __asm__("r0") = boot_command;
     __asm__ __volatile__("svc %0" ::"i"(SVC_REBOOT_TO_BOOTLOADER), "r"(r0)
                          : "memory");
   } else {
-    ensure_compatible_settings();
     _reboot_to_bootloader(boot_command);
   }
 }
@@ -83,7 +83,6 @@ void SVC_C_Handler(uint32_t *stack) {
         ;
       break;
     case SVC_REBOOT_TO_BOOTLOADER:
-      ensure_compatible_settings();
 
       __asm__ volatile("msr control, %0" ::"r"(0x0));
       __asm__ volatile("isb");

core/embed/trezorhal/stm32f4/xdisplay/st-7789/display_driver.c

@@ -43,40 +43,33 @@
 // Display driver instance
 display_driver_t g_display_driver;
 
-void display_init(void) {
+void display_init(display_content_mode_t mode) {
   display_driver_t* drv = &g_display_driver;
   memset(drv, 0, sizeof(display_driver_t));
 
-  display_io_init_gpio();
-  display_io_init_fmc();
-  display_panel_init();
-  display_panel_set_little_endian();
-  backlight_pwm_init(BACKLIGHT_RESET);
+  if (mode == DISPLAY_RESET_CONTENT) {
+    display_io_init_gpio();
+    display_io_init_fmc();
+    display_panel_init();
+    display_panel_set_little_endian();
+    backlight_pwm_init(BACKLIGHT_RESET);
+  } else {
+    // Reinitialize FMC to set correct timing
+    // We have to do this in reinit because boardloader is fixed.
+    display_io_init_fmc();
+
+    // Important for model T as this is not set in boardloader
+    display_panel_set_little_endian();
+    display_panel_reinit();
+    backlight_pwm_init(BACKLIGHT_RETAIN);
+  }
 
 #ifdef XFRAMEBUFFER
   display_io_init_te_interrupt();
 #endif
 }
 
-void display_reinit(void) {
-  display_driver_t* drv = &g_display_driver;
-  memset(drv, 0, sizeof(display_driver_t));
-
-  // Reinitialize FMC to set correct timing
-  // We have to do this in reinit because boardloader is fixed.
-  display_io_init_fmc();
-
-  // Important for model T as this is not set in boardloader
-  display_panel_set_little_endian();
-  display_panel_reinit();
-  backlight_pwm_init(BACKLIGHT_RETAIN);
-
-#ifdef XFRAMEBUFFER
-  display_io_init_te_interrupt();
-#endif
-}
-
-void display_finish_actions(void) {
+void display_deinit(display_content_mode_t mode) {
 #ifdef XFRAMEBUFFER
 #ifndef BOARDLOADER
   display_ensure_refreshed();

core/embed/trezorhal/stm32f4/xdisplay/stm32f429i-disc1/display_driver.c

@@ -44,24 +44,20 @@ typedef struct {
 // Display driver instance
 static display_driver_t g_display_driver;
 
-void display_init(void) {
+void display_init(display_content_mode_t mode) {
   display_driver_t *drv = &g_display_driver;
   memset(drv, 0, sizeof(display_driver_t));
   drv->framebuf = (uint16_t *)FRAME_BUFFER_ADDR;
 
-  // Initialize LTDC controller
-  BSP_LCD_Init();
-  // Initialize external display controller
-  ili9341_init();
+  if (mode == DISPLAY_RESET_CONTENT) {
+    // Initialize LTDC controller
+    BSP_LCD_Init();
+    // Initialize external display controller
+    ili9341_init();
+  }
 }
 
-void display_reinit(void) {
-  display_driver_t *drv = &g_display_driver;
-  memset(drv, 0, sizeof(display_driver_t));
-  drv->framebuf = (uint16_t *)FRAME_BUFFER_ADDR;
-}
-
-void display_finish_actions(void) {
+void display_deinit(display_content_mode_t mode) {
   // Not used and intentionally left empty
 }
 

core/embed/trezorhal/stm32f4/xdisplay/ug-2828/display_driver.c

@@ -291,25 +291,20 @@ static void display_init_interface(void) {
   HAL_SRAM_Init(&display_sram, &normal_mode_timing, NULL);
 }
 
-void display_init(void) {
+void display_init(display_content_mode_t mode) {
   display_driver_t *drv = &g_display_driver;
   memset(drv, 0, sizeof(display_driver_t));
 
-  // Initialize GPIO & FSMC controller
-  display_init_interface();
-  // Initialize display controller
-  display_init_controller();
+  if (mode == DISPLAY_RESET_CONTENT) {
+    // Initialize GPIO & FSMC controller
+    display_init_interface();
+    // Initialize display controller
+    display_init_controller();
+  }
 }
 
-void display_reinit(void) {
-  display_driver_t *drv = &g_display_driver;
-  memset(drv, 0, sizeof(display_driver_t));
-
-  // !@# TODO backlight level??
-}
-
-void display_finish_actions(void) {
-  /// Not used and intentionally left empty
+void display_deinit(display_content_mode_t mode) {
+  // Not used and intentionally left empty
 }
 
 int display_set_backlight(int level) {

core/embed/trezorhal/stm32f4/xdisplay/vg-2864/display_driver.c

@@ -220,84 +220,79 @@ static void display_sync_with_fb(display_driver_t *drv) {
   HAL_GPIO_WritePin(OLED_DC_PORT, OLED_DC_PIN, GPIO_PIN_RESET);
 }
 
-void display_init(void) {
+void display_init(display_content_mode_t mode) {
   display_driver_t *drv = &g_display_driver;
 
   memset(drv, 0, sizeof(display_driver_t));
   drv->backlight_level = 255;
 
-  OLED_DC_CLK_ENA();
-  OLED_CS_CLK_ENA();
-  OLED_RST_CLK_ENA();
-  OLED_SPI_SCK_CLK_ENA();
-  OLED_SPI_MOSI_CLK_ENA();
-  OLED_SPI_CLK_ENA();
+  if (mode == DISPLAY_RESET_CONTENT) {
+    OLED_DC_CLK_ENA();
+    OLED_CS_CLK_ENA();
+    OLED_RST_CLK_ENA();
+    OLED_SPI_SCK_CLK_ENA();
+    OLED_SPI_MOSI_CLK_ENA();
+    OLED_SPI_CLK_ENA();
 
-  GPIO_InitTypeDef GPIO_InitStructure;
+    GPIO_InitTypeDef GPIO_InitStructure;
 
-  // Set GPIO for OLED display
-  GPIO_InitStructure.Mode = GPIO_MODE_OUTPUT_PP;
-  GPIO_InitStructure.Pull = GPIO_NOPULL;
-  GPIO_InitStructure.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
-  GPIO_InitStructure.Alternate = 0;
-  GPIO_InitStructure.Pin = OLED_CS_PIN;
-  HAL_GPIO_WritePin(OLED_CS_PORT, OLED_CS_PIN, GPIO_PIN_RESET);
-  HAL_GPIO_Init(OLED_CS_PORT, &GPIO_InitStructure);
-  GPIO_InitStructure.Pin = OLED_DC_PIN;
-  HAL_GPIO_WritePin(OLED_DC_PORT, OLED_DC_PIN, GPIO_PIN_RESET);
-  HAL_GPIO_Init(OLED_DC_PORT, &GPIO_InitStructure);
-  GPIO_InitStructure.Pin = OLED_RST_PIN;
-  HAL_GPIO_WritePin(OLED_RST_PORT, OLED_RST_PIN, GPIO_PIN_RESET);
-  HAL_GPIO_Init(OLED_RST_PORT, &GPIO_InitStructure);
+    // Set GPIO for OLED display
+    GPIO_InitStructure.Mode = GPIO_MODE_OUTPUT_PP;
+    GPIO_InitStructure.Pull = GPIO_NOPULL;
+    GPIO_InitStructure.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
+    GPIO_InitStructure.Alternate = 0;
+    GPIO_InitStructure.Pin = OLED_CS_PIN;
+    HAL_GPIO_WritePin(OLED_CS_PORT, OLED_CS_PIN, GPIO_PIN_RESET);
+    HAL_GPIO_Init(OLED_CS_PORT, &GPIO_InitStructure);
+    GPIO_InitStructure.Pin = OLED_DC_PIN;
+    HAL_GPIO_WritePin(OLED_DC_PORT, OLED_DC_PIN, GPIO_PIN_RESET);
+    HAL_GPIO_Init(OLED_DC_PORT, &GPIO_InitStructure);
+    GPIO_InitStructure.Pin = OLED_RST_PIN;
+    HAL_GPIO_WritePin(OLED_RST_PORT, OLED_RST_PIN, GPIO_PIN_RESET);
+    HAL_GPIO_Init(OLED_RST_PORT, &GPIO_InitStructure);
 
-  // Enable SPI 1 for OLED display
-  GPIO_InitStructure.Mode = GPIO_MODE_AF_PP;
-  GPIO_InitStructure.Pull = GPIO_NOPULL;
-  GPIO_InitStructure.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
-  GPIO_InitStructure.Alternate = OLED_SPI_AF;
-  GPIO_InitStructure.Pin = OLED_SPI_SCK_PIN;
-  HAL_GPIO_Init(OLED_SPI_SCK_PORT, &GPIO_InitStructure);
-  GPIO_InitStructure.Pin = OLED_SPI_MOSI_PIN;
-  HAL_GPIO_Init(OLED_SPI_MOSI_PORT, &GPIO_InitStructure);
+    // Enable SPI 1 for OLED display
+    GPIO_InitStructure.Mode = GPIO_MODE_AF_PP;
+    GPIO_InitStructure.Pull = GPIO_NOPULL;
+    GPIO_InitStructure.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
+    GPIO_InitStructure.Alternate = OLED_SPI_AF;
+    GPIO_InitStructure.Pin = OLED_SPI_SCK_PIN;
+    HAL_GPIO_Init(OLED_SPI_SCK_PORT, &GPIO_InitStructure);
+    GPIO_InitStructure.Pin = OLED_SPI_MOSI_PIN;
+    HAL_GPIO_Init(OLED_SPI_MOSI_PORT, &GPIO_InitStructure);
 
-  // Initialize SPI controller
-  display_init_spi(drv);
+    // Initialize SPI controller
+    display_init_spi(drv);
 
-  // Set to CMD
-  HAL_GPIO_WritePin(OLED_DC_PORT, OLED_DC_PIN, GPIO_PIN_RESET);
-  // SPI deselect
-  HAL_GPIO_WritePin(OLED_CS_PORT, OLED_CS_PIN, GPIO_PIN_SET);
+    // Set to CMD
+    HAL_GPIO_WritePin(OLED_DC_PORT, OLED_DC_PIN, GPIO_PIN_RESET);
+    // SPI deselect
+    HAL_GPIO_WritePin(OLED_CS_PORT, OLED_CS_PIN, GPIO_PIN_SET);
 
-  // Reset the LCD
-  HAL_GPIO_WritePin(OLED_RST_PORT, OLED_RST_PIN, GPIO_PIN_SET);
-  HAL_Delay(1);
-  HAL_GPIO_WritePin(OLED_RST_PORT, OLED_RST_PIN, GPIO_PIN_RESET);
-  HAL_Delay(1);
-  HAL_GPIO_WritePin(OLED_RST_PORT, OLED_RST_PIN, GPIO_PIN_SET);
+    // Reset the LCD
+    HAL_GPIO_WritePin(OLED_RST_PORT, OLED_RST_PIN, GPIO_PIN_SET);
+    HAL_Delay(1);
+    HAL_GPIO_WritePin(OLED_RST_PORT, OLED_RST_PIN, GPIO_PIN_RESET);
+    HAL_Delay(1);
+    HAL_GPIO_WritePin(OLED_RST_PORT, OLED_RST_PIN, GPIO_PIN_SET);
 
-  // SPI select
-  HAL_GPIO_WritePin(OLED_CS_PORT, OLED_CS_PIN, GPIO_PIN_RESET);
-  // Send initialization command sequence
-  display_send_bytes(drv, &vg_2864ksweg01_init_seq[0],
-                     sizeof(vg_2864ksweg01_init_seq));
-  // SPI deselect
-  HAL_GPIO_WritePin(OLED_CS_PORT, OLED_CS_PIN, GPIO_PIN_SET);
+    // SPI select
+    HAL_GPIO_WritePin(OLED_CS_PORT, OLED_CS_PIN, GPIO_PIN_RESET);
+    // Send initialization command sequence
+    display_send_bytes(drv, &vg_2864ksweg01_init_seq[0],
+                       sizeof(vg_2864ksweg01_init_seq));
+    // SPI deselect
+    HAL_GPIO_WritePin(OLED_CS_PORT, OLED_CS_PIN, GPIO_PIN_SET);
 
-  // Clear display internal framebuffer
-  display_sync_with_fb(drv);
+    // Clear display internal framebuffer
+    display_sync_with_fb(drv);
+  } else {
+    display_init_spi(drv);
+  }
 }
 
-void display_reinit(void) {
-  display_driver_t *drv = &g_display_driver;
-
-  memset(drv, 0, sizeof(display_driver_t));
-  drv->backlight_level = 255;
-
-  display_init_spi(drv);
-}
-
-void display_finish_actions(void) {
-  /// Not used and intentionally left empty
+void display_deinit(display_content_mode_t mode) {
+  // Not used and intentionally left empty
 }
 
 int display_set_backlight(int level) {

core/embed/trezorhal/stm32u5/common.c

@@ -38,7 +38,7 @@ uint32_t systick_val_copy = 0;
 extern void shutdown_privileged(void);
 
 void __attribute__((noreturn)) trezor_shutdown(void) {
-  display_finish_actions();
+  display_deinit(DISPLAY_RETAIN_CONTENT);
 
   __HAL_RCC_SAES_CLK_DISABLE();
   // Erase all secrets

core/embed/trezorhal/stm32u5/displays/dsi.c

@@ -1654,7 +1654,7 @@ int display_orientation(int degrees) { return degrees; }
 int display_get_orientation(void) { return 0; }
 int display_backlight(int val) { return val; }
 
-void display_init(void) {
+void display_init_all(void) {
   RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
 
   /** Initializes the common periph clock

core/embed/trezorhal/stm32u5/xdisplay/stm32u5a9j-dk/display_driver.c

@@ -41,44 +41,49 @@ typedef struct {
 // Display driver instance
 static display_driver_t g_display_driver;
 
-void display_init(void) {
-  RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
+void display_init(display_content_mode_t mode) {
+  if (mode == DISPLAY_RESET_CONTENT) {
+    RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
 
-  // Initializes the common periph clock
-  PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_LTDC | RCC_PERIPHCLK_DSI;
-  PeriphClkInit.DsiClockSelection = RCC_DSICLKSOURCE_PLL3;
-  PeriphClkInit.LtdcClockSelection = RCC_LTDCCLKSOURCE_PLL3;
-  PeriphClkInit.PLL3.PLL3Source = RCC_PLLSOURCE_HSE;
-  PeriphClkInit.PLL3.PLL3M = 4;
-  PeriphClkInit.PLL3.PLL3N = 125;
-  PeriphClkInit.PLL3.PLL3P = 8;
-  PeriphClkInit.PLL3.PLL3Q = 2;
-  PeriphClkInit.PLL3.PLL3R = 24;
-  PeriphClkInit.PLL3.PLL3RGE = RCC_PLLVCIRANGE_0;
-  PeriphClkInit.PLL3.PLL3FRACN = 0;
-  PeriphClkInit.PLL3.PLL3ClockOut = RCC_PLL3_DIVP | RCC_PLL3_DIVR;
-  HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit);
+    // Initializes the common periph clock
+    PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_LTDC | RCC_PERIPHCLK_DSI;
+    PeriphClkInit.DsiClockSelection = RCC_DSICLKSOURCE_PLL3;
+    PeriphClkInit.LtdcClockSelection = RCC_LTDCCLKSOURCE_PLL3;
+    PeriphClkInit.PLL3.PLL3Source = RCC_PLLSOURCE_HSE;
+    PeriphClkInit.PLL3.PLL3M = 4;
+    PeriphClkInit.PLL3.PLL3N = 125;
+    PeriphClkInit.PLL3.PLL3P = 8;
+    PeriphClkInit.PLL3.PLL3Q = 2;
+    PeriphClkInit.PLL3.PLL3R = 24;
+    PeriphClkInit.PLL3.PLL3RGE = RCC_PLLVCIRANGE_0;
+    PeriphClkInit.PLL3.PLL3FRACN = 0;
+    PeriphClkInit.PLL3.PLL3ClockOut = RCC_PLL3_DIVP | RCC_PLL3_DIVR;
+    HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit);
 
-  // Clear framebuffers
-  memset(physical_frame_buffer_0, 0x00, PHYSICAL_FRAME_BUFFER_SIZE);
-  memset(physical_frame_buffer_1, 0x00, PHYSICAL_FRAME_BUFFER_SIZE);
+    // Clear framebuffers
+    memset(physical_frame_buffer_0, 0x00, PHYSICAL_FRAME_BUFFER_SIZE);
+    memset(physical_frame_buffer_1, 0x00, PHYSICAL_FRAME_BUFFER_SIZE);
 
-  BSP_LCD_Init(0, LCD_ORIENTATION_PORTRAIT);
-  BSP_LCD_SetBrightness(0, 100);
-  BSP_LCD_DisplayOn(0);
-}
-
-void display_reinit(void) {
-  BSP_LCD_Reinit(0);
-  if (current_frame_buffer == 0) {
-    BSP_LCD_SetFrameBuffer(0, GFXMMU_VIRTUAL_BUFFER1_BASE_S);
+    BSP_LCD_Init(0, LCD_ORIENTATION_PORTRAIT);
+    BSP_LCD_SetBrightness(0, 100);
+    BSP_LCD_DisplayOn(0);
   } else {
-    BSP_LCD_SetFrameBuffer(0, GFXMMU_VIRTUAL_BUFFER0_BASE_S);
+    // Retain display content
+    BSP_LCD_Reinit(0);
+    if (current_frame_buffer == 0) {
+      BSP_LCD_SetFrameBuffer(0, GFXMMU_VIRTUAL_BUFFER1_BASE_S);
+    } else {
+      BSP_LCD_SetFrameBuffer(0, GFXMMU_VIRTUAL_BUFFER0_BASE_S);
+    }
   }
 }
 
-void display_finish_actions(void) {
-  // Not used and intentionally left empty
+void display_deinit(display_content_mode_t mode) {
+  if (mode == DISPLAY_RESET_CONTENT) {
+    BSP_LCD_DisplayOff(0);
+    BSP_LCD_SetBrightness(0, 0);
+    BSP_LCD_DeInit(0);
+  }
 }
 
 int display_set_backlight(int level) {
@@ -112,8 +117,6 @@ int display_get_orientation(void) {
   return drv->orientation_angle;
 }
 
-void display_set_compatible_settings() {}
-
 void display_fill(const gfx_bitblt_t *bb) {
   display_fb_info_t fb = display_get_frame_buffer();
 

core/embed/trezorhal/stm32u5/xdisplay/stm32u5a9j-dk/display_internal.h

@@ -50,9 +50,11 @@ extern uint32_t current_frame_buffer;
 #define LCD_ORIENTATION_LANDSCAPE_ROT180 3U
 
 int32_t BSP_LCD_Init(uint32_t Instance, uint32_t Orientation);
+int32_t BSP_LCD_DeInit(uint32_t Instance);
 int32_t BSP_LCD_Reinit(uint32_t Instance);
 int32_t BSP_LCD_SetBrightness(uint32_t Instance, uint32_t Brightness);
 int32_t BSP_LCD_DisplayOn(uint32_t Instance);
+int32_t BSP_LCD_DisplayOff(uint32_t Instance);
 int32_t BSP_LCD_SetFrameBuffer(uint32_t Instance, uint32_t fb_addr);
 
 #endif  // TREZOR_HAL_DISPLAY_INTERNAL_H

core/embed/trezorhal/stm32u5/xdisplay/stm32u5a9j-dk/display_ltdc_dsi.c

@@ -202,6 +202,11 @@ static void DSI_EndOfRefreshCallback(DSI_HandleTypeDef *hdsi);
  * @retval BSP status.
  */
 int32_t BSP_LCD_Init(uint32_t Instance, uint32_t Orientation) {
+  memset(&hlcd_gfxmmu, 0, sizeof(hlcd_gfxmmu));
+  memset(&hlcd_ltdc, 0, sizeof(hlcd_ltdc));
+  memset(&hlcd_dsi, 0, sizeof(hlcd_dsi));
+  memset(&DSIVidCfg, 0, sizeof(DSIVidCfg));
+
   int32_t status = BSP_ERROR_NONE;
 
   if ((Instance >= LCD_INSTANCES_NBR) ||

core/embed/trezorhal/unix/display_driver.c

@@ -58,34 +58,18 @@ static display_driver_t g_display_driver;
 int sdl_display_res_x = DISPLAY_RESX, sdl_display_res_y = DISPLAY_RESY;
 int sdl_touch_offset_x, sdl_touch_offset_y;
 
-void display_deinit(void) {
-  display_driver_t *drv = &g_display_driver;
-
-  SDL_FreeSurface(drv->prev_saved);
-  SDL_FreeSurface(drv->buffer);
-  if (drv->background != NULL) {
-    SDL_DestroyTexture(drv->background);
-  }
-  if (drv->texture != NULL) {
-    SDL_DestroyTexture(drv->texture);
-  }
-  if (drv->renderer != NULL) {
-    SDL_DestroyRenderer(drv->renderer);
-  }
-  if (drv->window != NULL) {
-    SDL_DestroyWindow(drv->window);
-  }
-  SDL_Quit();
+static void display_exit_handler(void) {
+  display_deinit(DISPLAY_RESET_CONTENT);
 }
 
-void display_init(void) {
+void display_init(display_content_mode_t mode) {
   display_driver_t *drv = &g_display_driver;
 
   if (SDL_Init(SDL_INIT_VIDEO) != 0) {
     printf("%s\n", SDL_GetError());
     error_shutdown("SDL_Init error");
   }
-  atexit(display_deinit);
+  atexit(display_exit_handler);
 
   char *window_title = NULL;
   char *window_title_alloc = NULL;
@@ -162,12 +146,24 @@ void display_init(void) {
 #endif
 }
 
-void display_reinit(void) {
-  // not used
-}
+void display_deinit(display_content_mode_t mode) {
+  display_driver_t *drv = &g_display_driver;
 
-void display_finish_actions(void) {
-  // not used
+  SDL_FreeSurface(drv->prev_saved);
+  SDL_FreeSurface(drv->buffer);
+  if (drv->background != NULL) {
+    SDL_DestroyTexture(drv->background);
+  }
+  if (drv->texture != NULL) {
+    SDL_DestroyTexture(drv->texture);
+  }
+  if (drv->renderer != NULL) {
+    SDL_DestroyRenderer(drv->renderer);
+  }
+  if (drv->window != NULL) {
+    SDL_DestroyWindow(drv->window);
+  }
+  SDL_Quit();
 }
 
 int display_set_backlight(int level) {

core/embed/trezorhal/xdisplay.h

@@ -46,18 +46,28 @@
 // MIPI            -
 //                 - STM32U5A9J-DK Discovery Board
 
-// Fully initializes the display controller.
-void display_init(void);
+// Specifies how display content should be handled during
+// initialization or deinitialization.
+typedef enum {
+  // Clear the display content
+  DISPLAY_RESET_CONTENT,
+  // Retain the display content
+  DISPLAY_RETAIN_CONTENT
+} display_content_mode_t;
 
-// Called in application or bootloader to reinitialize an already initialized
-// display controller without any distrubing visible effect (blinking, etc.).
-void display_reinit(void);
-
-// Waits for any backround operations (such as DMA copying) and returns.
+// Initializes the display controller.
 //
-// The function provides a barrier when jumping between
-// boardloader/bootloader and firmware.
-void display_finish_actions(void);
+// If `mode` is `DISPLAY_RETAIN_CONTENT`, ensure the driver was previously
+// initialized and `display_deinit(DISPLAY_RETAIN_CONTENT)` was called.
+void display_init(display_content_mode_t mode);
+
+// Deinitializes the display controller.
+//
+// If `mode` is `DISPLAY_RETAIN_CONTENT`, the function waits for
+// background operations to complete and disables interrupts, so the
+//  application can safely proceed to the next boot stage and call
+// `display_init(DISPLAY_RETAIN_CONTENT)`.
+void display_deinit(display_content_mode_t mode);
 
 // Sets display backlight level ranging from 0 (off)..255 (maximum).
 //
@@ -122,7 +132,7 @@ void display_refresh(void);
 // This is used when switching between the firmware and the bootloader.
 void display_set_compatible_settings(void);
 
-// Following function define display's bitblt interface.
+// Following functions define display's bitblt interface.
 //
 // These functions draw directly to to display or to the
 // currently inactive framebuffer.

core/embed/trezorhal/xdisplay_legacy.h

@@ -23,12 +23,12 @@
 #include <buffers.h>
 #include <stdint.h>
 
-// These declarationscode emulates will be removed after the
-// final cleanup of display drivers. They are here just to simplify
-// integration with the legacy code.
+// These declarations will be removed after the final cleanup
+// of display drivers. They are here just to simplify integration
+// with the legacy code.
 //
-// Most of these function are not called when NEW_RENDERING=1
-// and they are only needed to for succesfully code compilation
+// Most of these functions are not called when NEW_RENDERING=1,
+// and they are only needed for successful code compilation.
 
 #define DISPLAY_FRAMEBUFFER_WIDTH 768
 #define DISPLAY_FRAMEBUFFER_HEIGHT 480

core/embed/unix/main.c

@@ -486,7 +486,7 @@ MP_NOINLINE int main_(int argc, char **argv) {
 
   pre_process_options(argc, argv);
 
-  display_init();
+  display_init(DISPLAY_RESET_CONTENT);
 
 #if USE_TOUCH
   touch_init();