Merge pull request adafruit#10277 from tannewt/disable_audio_dma_channels

Run background tasks during display refresh

Author: dhalbert

ports/raspberrypi/audio_dma.c

@@ -159,9 +159,13 @@ static void audio_dma_load_next_block(audio_dma_t *dma, size_t buffer_idx) {
                 !dma_channel_is_busy(dma->channel[1])) {
                 // No data has been read, and both DMA channels have now finished, so it's safe to stop.
                 audio_dma_stop(dma);
+                dma->dma_result = AUDIO_DMA_OK;
+                return;
             }
         }
     }
+    // Enable the channel so that it can be played.
+    dma_hw->ch[dma_channel].al1_ctrl |= DMA_CH1_CTRL_TRIG_EN_BITS;
     dma->dma_result = AUDIO_DMA_OK;
 }
 
@@ -495,18 +499,26 @@ static void dma_callback_fun(void *arg) {
 
     // Load the blocks for the requested channels.
     uint32_t channel = 0;
+    size_t filled_count = 0;
     while (channels_to_load_mask) {
         if (channels_to_load_mask & 1) {
             if (dma->channel[0] == channel) {
                 audio_dma_load_next_block(dma, 0);
+                filled_count++;
             }
             if (dma->channel[1] == channel) {
                 audio_dma_load_next_block(dma, 1);
+                filled_count++;
             }
         }
         channels_to_load_mask >>= 1;
         channel++;
     }
+    // If we had to fill both buffers, then we missed the trigger from the other
+    // buffer. So restart the DMA.
+    if (filled_count == 2) {
+        dma_channel_start(dma->channel[0]);
+    }
 }
 
 void __not_in_flash_func(isr_dma_0)(void) {
@@ -524,6 +536,8 @@ void __not_in_flash_func(isr_dma_0)(void) {
             audio_dma_t *dma = MP_STATE_PORT(playing_audio)[i];
             // Record all channels whose DMA has completed; they need loading.
             dma->channels_to_load_mask |= mask;
+            // Disable the channel so that we don't play it without filling it.
+            dma_hw->ch[i].al1_ctrl &= ~DMA_CH0_CTRL_TRIG_EN_BITS;
             background_callback_add(&dma->callback, dma_callback_fun, (void *)dma);
         }
         if (MP_STATE_PORT(background_pio_read)[i] != NULL) {

shared-module/busdisplay/BusDisplay.c

@@ -296,8 +296,11 @@ static bool _refresh_area(busdisplay_busdisplay_obj_t *self, const displayio_are
         _send_pixels(self, (uint8_t *)buffer, subrectangle_size_bytes);
         displayio_display_bus_end_transaction(&self->bus);
 
-        // TODO(tannewt): Make refresh displays faster so we don't starve other
-        // background tasks.
+        // Run background tasks so they can run during an explicit refresh.
+        // Auto-refresh won't run background tasks here because it is a background task itself.
+        RUN_BACKGROUND_TASKS;
+
+        // Run USB background tasks so they can run during an implicit refresh.
         #if CIRCUITPY_TINYUSB
         usb_background();
         #endif

shared-module/epaperdisplay/EPaperDisplay.c

@@ -360,8 +360,11 @@ static bool epaperdisplay_epaperdisplay_refresh_area(epaperdisplay_epaperdisplay
             self->bus.send(self->bus.bus, DISPLAY_DATA, self->chip_select, (uint8_t *)buffer, subrectangle_size_bytes);
             displayio_display_bus_end_transaction(&self->bus);
 
-            // TODO(tannewt): Make refresh displays faster so we don't starve other
-            // background tasks.
+            // Run background tasks so they can run during an explicit refresh.
+            // Auto-refresh won't run background tasks here because it is a background task itself.
+            RUN_BACKGROUND_TASKS;
+
+            // Run USB background tasks so they can run during an implicit refresh.
             #if CIRCUITPY_TINYUSB
             usb_background();
             #endif

shared-module/framebufferio/FramebufferDisplay.c

@@ -200,9 +200,11 @@ static bool _refresh_area(framebufferio_framebufferdisplay_obj_t *self, const di
             dest += rowstride;
             src += rowsize;
         }
+        // Run background tasks so they can run during an explicit refresh.
+        // Auto-refresh won't run background tasks here because it is a background task itself.
+        RUN_BACKGROUND_TASKS;
 
-        // TODO(tannewt): Make refresh displays faster so we don't starve other
-        // background tasks.
+        // Run USB background tasks so they can run during an implicit refresh.
         #if CIRCUITPY_TINYUSB
         usb_background();
         #endif