canonselphy: Send the error recovery/reset sequence after an error occurs.

And add error recovery code for the CP-10.

(I wonder if the ES series uses the same reset sequence?)

backend_canonselphy.c

@@ -284,8 +284,9 @@ static struct printer_data selphy_printers[] = {
 	  .ready_m_readback = { 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 	  .ready_c_readback = { 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 	  .done_c_readback = { 0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+	  .clear_error = { 0x40, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+	  .clear_error_len = 12,
 	  // .paper_codes
-	  // .clear_error + clear_error_len
 	  .pgcode_offset = -1,
 	  .paper_code_offset = -1,
 	  .error_detect = cp10_error_detect,
@@ -642,16 +643,6 @@ static int canonselphy_main_loop(void *vctx, int copies) {
 	if (ret < 0)
 		return ret;
 
-#if 0 /* This doesn't work yet */
-	/* Error detection & (possible) recovery */
-	if (ctx->printer->error_detect(rdbuf)) {
-		if (ctx->printer->clear_error_len)
-			/* Try to clear error state */
-			if ((ret = send_data(ctx->dev, ctx->endp_down, ctx->printer->clear_error, ctx->printer->clear_error_len)))
-				return ret;
-	}
-#endif
-
 top:
 
 	if (state != last_state) {
@@ -671,8 +662,13 @@ top:
 	}
 
 	/* Error detection */
-	if (ctx->printer->error_detect(rdbuf))
+	if (ctx->printer->error_detect(rdbuf)) {
+		if (ctx->printer->clear_error_len)
+			/* Try to clear error state */
+			if ((ret = send_data(ctx->dev, ctx->endp_down, ctx->printer->clear_error, ctx->printer->clear_error_len)))
+				return ret;
 		return 4;
+	}
 
 	if (memcmp(rdbuf, rdbuf2, READBACK_LEN)) {
 		memcpy(rdbuf2, rdbuf, READBACK_LEN);
@@ -859,7 +855,7 @@ top:
 
 struct dyesub_backend canonselphy_backend = {
 	.name = "Canon SELPHY CP/ES",
-	.version = "0.75",
+	.version = "0.76",
 	.uri_prefix = "canonselphy",
 	.init = canonselphy_init,
 	.attach = canonselphy_attach,
@@ -1133,6 +1129,8 @@ struct dyesub_backend canonselphy_backend = {
 
    length is always '00 60 81 0a' which is 688480 bytes.
 
+   Error clear: 40 10 00 00  00 00 00 00  00 00 00 00
+
    Known readback values:
 
    01 00 00 00  00 00 00 00  00 00 00 00   [idle, waiting for init]
@@ -1160,7 +1158,7 @@ struct dyesub_backend canonselphy_backend = {
    Plane func:  40 01 00 [plane]  [length, 32-bit LE]  00 00 00 00 
    End func:    00 00 00 00      # NOTE:  CP900 only, and not necessary!
 
-   Error clear: 40 10 00 00  00 00 00 00  00 00 00 00  # CP800.  Others?
+   Error clear: 40 10 00 00  00 00 00 00  00 00 00 00
 
    plane codes are 0x00, 0x01, 0x02 for Y, M, and C, respectively.