From 0e314c2f32184b061328b1b6d465af56e1653555 Mon Sep 17 00:00:00 2001
From: Thomas Farstrike <thomasverstreken@protonmail.com>
Date: Wed, 14 May 2025 08:44:23 +0200
Subject: [PATCH] Revert "Simplification no longer works"

This reverts commit 36de2488e259ee25cd6312c7bc123f0255deb42b.
---
 c_mpos/src/webcam.c | 38 +++++++++++++++++++++++---------------
 1 file changed, 23 insertions(+), 15 deletions(-)

diff --git a/c_mpos/src/webcam.c b/c_mpos/src/webcam.c
index 7fcd05db..5b7085b9 100644
--- a/c_mpos/src/webcam.c
+++ b/c_mpos/src/webcam.c
@@ -23,7 +23,9 @@
 #define CAPTURE_HEIGHT 480
 #define OUTPUT_WIDTH 240   // Resize to 240x240
 #define OUTPUT_HEIGHT 240
-#define NUM_BUFFERS 2      // Keep 2 buffers, stable for continuous captures
+#define NUM_BUFFERS 2      // Revert to 2 buffers, as it achieved 2 captures
+#define QUEUE_RETRIES 10   // Increase retries for robustness
+#define QUEUE_RETRY_DELAY_US 200000  // 200ms delay between retries
 
 // Webcam object type
 typedef struct _webcam_obj_t {
@@ -96,28 +98,34 @@ static void webcam_reset_streaming(webcam_obj_t *self) {
 static mp_obj_t webcam_capture_grayscale(mp_obj_t self_in) {
     webcam_obj_t *self = MP_OBJ_TO_PTR(self_in);
 
-    // Try to queue a buffer
+    // Try to queue a buffer with retries
     struct v4l2_buffer buf = {0};
     bool queued = false;
-    for (size_t i = 0; i < self->num_buffers; i++) {
-        memset(&buf, 0, sizeof(buf));
-        buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
-        buf.memory = V4L2_MEMORY_MMAP;
-        buf.index = i;
+    for (int attempt = 0; attempt < QUEUE_RETRIES && !queued; attempt++) {
+        for (size_t i = 0; i < self->num_buffers; i++) {
+            memset(&buf, 0, sizeof(buf));
+            buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+            buf.memory = V4L2_MEMORY_MMAP;
+            buf.index = i;
 
-        WEBCAM_DEBUG_PRINT("webcam: Attempting to queue buffer (index=%zu)\n", i);
-        if (ioctl(self->fd, VIDIOC_QBUF, &buf) == 0) {
-            WEBCAM_DEBUG_PRINT("webcam: Successfully queued buffer (index=%zu)\n", i);
-            queued = true;
-            break;
+            WEBCAM_DEBUG_PRINT("webcam: Attempting to queue buffer (index=%zu, attempt=%d)\n", i, attempt + 1);
+            if (ioctl(self->fd, VIDIOC_QBUF, &buf) == 0) {
+                WEBCAM_DEBUG_PRINT("webcam: Successfully queued buffer (index=%zu)\n", i);
+                queued = true;
+                break;
+            }
+            WEBCAM_DEBUG_PRINT("webcam: Failed to queue buffer (index=%zu, errno=%d)\n", i, errno);
+        }
+        if (!queued && attempt < QUEUE_RETRIES - 1) {
+            WEBCAM_DEBUG_PRINT("webcam: No buffers available, retrying after delay\n");
+            usleep(QUEUE_RETRY_DELAY_US); // Wait 200ms
         }
-        WEBCAM_DEBUG_PRINT("webcam: Failed to queue buffer (index=%zu, errno=%d)\n", i, errno);
     }
 
     if (!queued) {
-        WEBCAM_DEBUG_PRINT("webcam: No buffers available, resetting streaming\n");
+        WEBCAM_DEBUG_PRINT("webcam: No buffers available after %d retries, resetting streaming\n", QUEUE_RETRIES);
         webcam_reset_streaming(self);
-        // Try queuing again after reset
+        // Retry queuing one more time after reset
         for (size_t i = 0; i < self->num_buffers; i++) {
             memset(&buf, 0, sizeof(buf));
             buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;