drivers: display: display_sdl: implement display_show

Adds frame synchronization to every frame. This prevents frame tearing. Signed-off-by: Martin Stumpf <[email protected]>
zephyrproject-rtos · Nov 11, 2024 · 56465bb · 56465bb
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commit 56465bb
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Showing 4 changed files with 69 additions and 32 deletions.
diff --git a/doc/releases/release-notes-4.1.rst b/doc/releases/release-notes-4.1.rst
@@ -95,6 +95,8 @@ Drivers and Sensors
   * Added API function :c:func:`display_show` and display capability
     :c:enum:`SCREEN_INFO_REQUIRES_SHOW` for displays that allow tearing prevention of segmented
     updates. (:github:`79936`)
+  * Implemented :c:func:`display_show` for SDL display driver (:dtcompatible:`zephyr,sdl-dc`)
+    and added display capability :c:enum:`SCREEN_INFO_REQUIRES_SHOW`. (:github:`79936`)
 
 * Ethernet
 

diff --git a/drivers/display/display_sdl.c b/drivers/display/display_sdl.c
@@ -260,9 +260,20 @@ static int sdl_display_write(const struct device *dev, const uint16_t x,
 		sdl_display_write_bgr565(disp_data->buf, desc, buf);
 	}
 
-	sdl_display_write_bottom(desc->height, desc->width, x, y,
-				 disp_data->renderer, disp_data->mutex, disp_data->texture,
-				 disp_data->buf, disp_data->display_on);
+	sdl_display_write_bottom(desc->height, desc->width, x, y, disp_data->renderer,
+				 disp_data->mutex, disp_data->texture, disp_data->buf);
+
+	return 0;
+}
+
+static int sdl_display_show(const struct device *dev)
+{
+	struct sdl_display_data *disp_data = dev->data;
+
+	LOG_DBG("Displaying frame buffer content");
+
+	sdl_display_show_bottom(disp_data->renderer, disp_data->texture, disp_data->mutex,
+				disp_data->display_on);
 
 	return 0;
 }
@@ -431,7 +442,7 @@ static int sdl_display_blanking_off(const struct device *dev)
 
 	disp_data->display_on = true;
 
-	sdl_display_blanking_off_bottom(disp_data->renderer, disp_data->texture);
+	sdl_display_blanking_off_bottom(disp_data->renderer, disp_data->texture, disp_data->mutex);
 
 	return 0;
 }
@@ -444,7 +455,7 @@ static int sdl_display_blanking_on(const struct device *dev)
 
 	disp_data->display_on = false;
 
-	sdl_display_blanking_on_bottom(disp_data->renderer);
+	sdl_display_blanking_on_bottom(disp_data->renderer, disp_data->mutex);
 	return 0;
 }
 
@@ -464,8 +475,10 @@ static void sdl_display_get_capabilities(
 		PIXEL_FORMAT_RGB_565 |
 		PIXEL_FORMAT_BGR_565;
 	capabilities->current_pixel_format = disp_data->current_pixel_format;
-	capabilities->screen_info = SCREEN_INFO_MONO_VTILED |
-		(IS_ENABLED(CONFIG_SDL_DISPLAY_MONO_MSB_FIRST) ? SCREEN_INFO_MONO_MSB_FIRST : 0);
+	capabilities->screen_info =
+		SCREEN_INFO_MONO_VTILED |
+		(IS_ENABLED(CONFIG_SDL_DISPLAY_MONO_MSB_FIRST) ? SCREEN_INFO_MONO_MSB_FIRST : 0) |
+		SCREEN_INFO_REQUIRES_SHOW;
 }
 
 static int sdl_display_set_pixel_format(const struct device *dev,
@@ -499,6 +512,7 @@ static const struct display_driver_api sdl_display_api = {
 	.blanking_off = sdl_display_blanking_off,
 	.write = sdl_display_write,
 	.read = sdl_display_read,
+	.show = sdl_display_show,
 	.get_capabilities = sdl_display_get_capabilities,
 	.set_pixel_format = sdl_display_set_pixel_format,
 };

diff --git a/drivers/display/display_sdl_bottom.c b/drivers/display/display_sdl_bottom.c
@@ -5,6 +5,8 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include "display_sdl_bottom.h"
+
 #include <stdint.h>
 #include <stddef.h>
 #include <stdbool.h>
@@ -64,10 +66,9 @@ int sdl_display_init_bottom(uint16_t height, uint16_t width, uint16_t zoom_pct,
 	return 0;
 }
 
-void sdl_display_write_bottom(const uint16_t height, const uint16_t width,
-			      const uint16_t x, const uint16_t y,
-			      void *renderer, void *mutex, void *texture,
-			      uint8_t *buf, bool display_on)
+void sdl_display_write_bottom(const uint16_t height, const uint16_t width, const uint16_t x,
+			      const uint16_t y, void *renderer, void *mutex, void *texture,
+			      uint8_t *buf)
 {
 	SDL_Rect rect;
 	int err;
@@ -85,12 +86,6 @@ void sdl_display_write_bottom(const uint16_t height, const uint16_t width,
 
 	SDL_UpdateTexture(texture, &rect, buf, 4 * rect.w);
 
-	if (display_on) {
-		SDL_RenderClear(renderer);
-		SDL_RenderCopy(renderer, texture, NULL, NULL);
-		SDL_RenderPresent(renderer);
-	}
-
 	SDL_UnlockMutex(mutex);
 }
 
@@ -126,17 +121,44 @@ int sdl_display_read_bottom(const uint16_t height, const uint16_t width,
 	return err;
 }
 
-void sdl_display_blanking_off_bottom(void *renderer, void *texture)
+void sdl_display_show_bottom(void *renderer, void *texture, void *mutex, bool display_on)
 {
-	SDL_RenderClear(renderer);
-	SDL_RenderCopy(renderer, texture, NULL, NULL);
-	SDL_RenderPresent(renderer);
+	int err = 0;
+
+	if (display_on) {
+		err = SDL_TryLockMutex(mutex);
+		if (err) {
+			nsi_print_warning("Failed to lock SDL mutex: %s", SDL_GetError());
+			return;
+		}
+
+		SDL_RenderClear(renderer);
+		SDL_RenderCopy(renderer, texture, NULL, NULL);
+		SDL_RenderPresent(renderer);
+
+		SDL_UnlockMutex(mutex);
+	}
+}
+
+void sdl_display_blanking_off_bottom(void *renderer, void *texture, void *mutex)
+{
+	sdl_display_show_bottom(renderer, texture, mutex, true);
 }
 
-void sdl_display_blanking_on_bottom(void *renderer)
+void sdl_display_blanking_on_bottom(void *renderer, void *mutex)
 {
+	int err;
+
+	err = SDL_TryLockMutex(mutex);
+	if (err) {
+		nsi_print_warning("Failed to lock SDL mutex: %s", SDL_GetError());
+		return;
+	}
+
 	SDL_RenderClear(renderer);
 	SDL_RenderPresent(renderer);
+
+	SDL_UnlockMutex(mutex);
 }
 
 void sdl_display_cleanup_bottom(void **window, void **renderer, void **mutex, void **texture,

diff --git a/drivers/display/display_sdl_bottom.h b/drivers/display/display_sdl_bottom.h
@@ -23,16 +23,15 @@ extern "C" {
 int sdl_display_init_bottom(uint16_t height, uint16_t width, uint16_t zoom_pct,
 			    bool use_accelerator, void **window, void **renderer, void **mutex,
 			    void **texture, void **read_texture);
-void sdl_display_write_bottom(const uint16_t height, const uint16_t width,
-			      const uint16_t x, const uint16_t y,
-			      void *renderer, void *mutex, void *texture,
-			      uint8_t *buf, bool display_on);
-int sdl_display_read_bottom(const uint16_t height, const uint16_t width,
-			    const uint16_t x, const uint16_t y,
-			    void *renderer, void *buf, uint16_t pitch,
-			    void *mutex, void *texture, void **read_texture);
-void sdl_display_blanking_off_bottom(void *renderer, void *texture);
-void sdl_display_blanking_on_bottom(void *renderer);
+void sdl_display_write_bottom(const uint16_t height, const uint16_t width, const uint16_t x,
+			      const uint16_t y, void *renderer, void *mutex, void *texture,
+			      uint8_t *buf);
+void sdl_display_show_bottom(void *renderer, void *texture, void *mutex, bool display_on);
+int sdl_display_read_bottom(const uint16_t height, const uint16_t width, const uint16_t x,
+			    const uint16_t y, void *renderer, void *buf, uint16_t pitch,
+			    void *mutex, void *texture, void *read_texture);
+void sdl_display_blanking_off_bottom(void *renderer, void *texture, void *mutex);
+void sdl_display_blanking_on_bottom(void *renderer, void *mutex);
 void sdl_display_cleanup_bottom(void **window, void **renderer, void **mutex, void **texture,
 				void **read_texture);