feat(mipi_dsi): enable underrun error interrupt

Author: suda-morris

components/esp_lcd/dsi/esp_lcd_mipi_dsi_bus.c

@@ -16,7 +16,7 @@ static const char *TAG = "lcd.dsi.bus";
 
 #define MIPI_DSI_DEFAULT_TIMEOUT_CLOCK_FREQ_MHZ 10
 // TxClkEsc frequency must be configured between 2 and 20 MHz
-#define MIPI_DSI_DEFAULT_ESCAPE_CLOCK_FREQ_MHZ  10
+#define MIPI_DSI_DEFAULT_ESCAPE_CLOCK_FREQ_MHZ  18
 
 esp_err_t esp_lcd_new_dsi_bus(const esp_lcd_dsi_bus_config_t *bus_config, esp_lcd_dsi_bus_handle_t *ret_bus)
 {

components/esp_lcd/dsi/esp_lcd_panel_dpi.c

@@ -80,9 +80,20 @@ static bool dma_trans_done_cb(dw_gdma_channel_handle_t chan, const dw_gdma_trans
 {
     bool yield_needed = false;
     esp_lcd_dpi_panel_t *dpi_panel = (esp_lcd_dpi_panel_t *)user_data;
+    mipi_dsi_hal_context_t *hal = &dpi_panel->bus->hal;
     uint8_t fb_index = dpi_panel->cur_fb_index;
     dw_gdma_link_list_handle_t link_list = dpi_panel->link_lists[fb_index];
 
+    // clear the interrupt status
+    uint32_t error_status = mipi_dsi_brg_ll_get_interrupt_status(hal->bridge);
+    mipi_dsi_brg_ll_clear_interrupt_status(hal->bridge, error_status);
+    if (unlikely(error_status & MIPI_DSI_LL_EVENT_UNDERRUN)) {
+        // when an underrun happens, the LCD display may already becomes blue
+        // it's too late to recover the display, so we just print an error message
+        // as a hint to the user that he should optimize the memory bandwidth (with AXI-ICM)
+        ESP_DRAM_LOGE(TAG, "can't fetch data from external memory fast enough, underrun happens");
+    }
+
     // restart the DMA transfer, keep refreshing the LCD
     dw_gdma_block_markers_t markers = {
         .is_valid = true,
@@ -440,6 +451,10 @@ static esp_err_t dpi_panel_init(esp_lcd_panel_t *panel)
     mipi_dsi_brg_ll_enable_dpi_output(hal->bridge, true);
     mipi_dsi_brg_ll_update_dpi_config(hal->bridge);
 
+    // enable the underrun interrupt, we use this as a signal of bandwidth shortage
+    // note, we opt to not install a dedicated interrupt handler just for this error condition, instead, we check it in the DMA callback
+    mipi_dsi_brg_ll_enable_interrupt(hal->bridge, MIPI_DSI_LL_EVENT_UNDERRUN, true);
+
     return ESP_OK;
 }
 

components/hal/esp32p4/include/hal/mipi_dsi_host_ll.h

@@ -82,7 +82,7 @@ static inline void mipi_dsi_host_ll_power_on_off(dsi_host_dev_t *dev, bool on)
  */
 static inline void mipi_dsi_host_ll_set_timeout_clock_division(dsi_host_dev_t *dev, uint32_t div)
 {
-    HAL_FORCE_MODIFY_U32_REG_FIELD(dev->clkmgr_cfg, to_clk_division, div - 1);
+    HAL_FORCE_MODIFY_U32_REG_FIELD(dev->clkmgr_cfg, to_clk_division, div);
 }
 
 /**
@@ -95,7 +95,8 @@ static inline void mipi_dsi_host_ll_set_timeout_clock_division(dsi_host_dev_t *d
  */
 static inline void mipi_dsi_host_ll_set_escape_clock_division(dsi_host_dev_t *dev, uint32_t div)
 {
-    HAL_FORCE_MODIFY_U32_REG_FIELD(dev->clkmgr_cfg, tx_esc_clk_division, div - 1);
+    HAL_ASSERT(div > 1 && div < 256);
+    HAL_FORCE_MODIFY_U32_REG_FIELD(dev->clkmgr_cfg, tx_esc_clk_division, div);
 }
 
 /**

examples/peripherals/lcd/mipi_dsi/main/idf_component.yml

@@ -1,4 +1,4 @@
 dependencies:
-  lvgl/lvgl: "9.2.0"
+  lvgl/lvgl: "9.2.2"
   esp_lcd_ili9881c: "^1.0.0"
   esp_lcd_ek79007: "^1.0.0"