sdcardio internal init_card_v2 maximum potential timeout is ridiculously long

[hyx0329]

CircuitPython version

Adafruit CircuitPython 9.0.3(git tag), custom build for a RP2040 board

Code/REPL

import board
import sdcardio

bus = board.SPI()
# Run this, but do not connect the SD card's power
sd = sdcardio.SDCard(bus, board.SD_CS)

Behavior

No output, just stuck, for around 3 minutes

Description

No output, just stuck, for around 3 minutes. I think I found the cause, read more below. But I don't know how to improve it.

Additional information

In init_card_v2, the maximum potential timeout is given by CMD_TIMEOUT * (50ms + 3 cmd with wait), which is 200 * (50ms + 3 * 300ms) = 190 seconds. That's more than 3 minutes.

circuitpython/shared-module/sdcardio/SDCard.c

Lines 213 to 228 in 5836f11

	STATIC mp_rom_error_text_t init_card_v2(sdcardio_sdcard_obj_t *self) {
	for (int i = 0; i < CMD_TIMEOUT; i++) {
	uint8_t ocr[4];
	common_hal_time_delay_ms(50);
	cmd(self, 58, 0, ocr, sizeof(ocr), false, true);
	cmd(self, 55, 0, NULL, 0, true, true);
	if (cmd(self, 41, 0x40000000, NULL, 0, true, true) == 0) {
	cmd(self, 58, 0, ocr, sizeof(ocr), false, true);
	if ((ocr[0] & 0x40) != 0) {
	self->cdv = 1;
	}
	return NULL;
	}
	}
	return MP_ERROR_TEXT("timeout waiting for v2 card");
	}

[hyx0329]

Here's my current workaound

EDIT: I won't mind if someone just pick this and make a pr. But I doubt that having 2 types of time limits in a single function is appropriate.

diff --git a/shared-module/sdcardio/SDCard.c b/shared-module/sdcardio/SDCard.c
index 20c5afef0e..fc886964de 100644
--- a/shared-module/sdcardio/SDCard.c
+++ b/shared-module/sdcardio/SDCard.c
@@ -210,18 +210,26 @@ STATIC mp_rom_error_text_t init_card_v1(sdcardio_sdcard_obj_t *self) {
     return MP_ERROR_TEXT("timeout waiting for v1 card");
 }
 
+#define INIT_CARD_V2_ERROR_RETRY 5
 STATIC mp_rom_error_text_t init_card_v2(sdcardio_sdcard_obj_t *self) {
+    int early_error = 0;
     for (int i = 0; i < CMD_TIMEOUT; i++) {
         uint8_t ocr[4];
         common_hal_time_delay_ms(50);
-        cmd(self, 58, 0, ocr, sizeof(ocr), false, true);
-        cmd(self, 55, 0, NULL, 0, true, true);
-        if (cmd(self, 41, 0x40000000, NULL, 0, true, true) == 0) {
+        if (cmd(self, 58, 0, ocr, sizeof(ocr), false, true) >= 0
+            && cmd(self, 55, 0, NULL, 0, true, true) != -ETIMEDOUT
+            && cmd(self, 41, 0x40000000, NULL, 0, true, true) == 0) {
+
             cmd(self, 58, 0, ocr, sizeof(ocr), false, true);
             if ((ocr[0] & 0x40) != 0) {
                 self->cdv = 1;
             }
             return NULL;
+        } else {
+            early_error++;
+            if (early_error >= INIT_CARD_V2_ERROR_RETRY) {
+                break;
+            }
         }
     }
     return MP_ERROR_TEXT("timeout waiting for v2 card");