timeout waiting for v2 card since 236dec0 "shorten SDCard SPI timeouts, ..."

[bablokb]

CircuitPython version and board name

10.2.0-rc
Pico2

Code/REPL

import sdcardio
import storage
import busio
SD_MOSI = board.GP19
SD_SCK  = board.GP18
SD_MISO = board.GP16
SD_CS   = board.GP17

spi0 = busio.SPI(SD_SCK,SD_MOSI,SD_MISO)
sdcard = sdcardio.SDCard(spi0,SD_CS,1_000_000)
vfs    = storage.VfsFat(sdcard)
storage.mount(vfs, "/sd")

Behavior

Fails with "timeout waiting for v2 card"

Description

Reverting the timeout CMD_TIMEOUT_MS back to 500 from 250 fixes the issue. I did not change anything else, maybe this should be investigated further.

This is a normal 16GB SanDisk Ultra. I use many of these and never had any problems.

Additional information

Diff from the PR:

- #define CMD_TIMEOUT_MS (500)
- #define TIMEOUT_MS (500)
- #define SPI_TIMEOUT_MS (10000)
+ #define CMD_TIMEOUT_MS (250)
+ #define SPI_TIMEOUT_MS (250)
+ // Init ready timeout.
+ #define READY_TIMEOUT_MS (300)

[dhalbert]

I'm trying to reproduce this, so far unsuccessfully. The only SanDisk card I I have is an Ultra Plus 16GB. I had tested this with a bunch of Micro Center cards and the really small (e.g. 64MB) Adafruit cards.

In the sample code above,

• import board is missing, so maybe this is not the whole program?
• Why did you set the SPI baudrate to 1 MHz? The default is 8 MHz. (Maybe you were trying to get it to work?)

Thanks.

[bablokb]

This is not the complete program. I only copied the relevant part to show that I am not doing anything extra-ordinary. I honestly don't remember why the baudrate is 1MHz, the program is rather old.

One thing I noted: after a hard reset it fails. When I then use CTRL-D in the REPL to restart immediately, it works.

Another thing I noticed: the title of the commit 236dec0 states "remove RUN_BACKGROUND_TASKS in SDCard". But the code for init_card_v2() (that is where the error is triggered) uses mp_hal_delay_ms() which in turn runs background tasks. I don't understand enough about what is going on behind the scenes. Is it guaranteed that the background tasks only run for the specified time (in this case 50ms)? If not, could it be that long running background tasks prevent the loop in init_card_v2() to retry enough times?