sdcardio: "OSError: can't set 512 block size" for some 32GB cards after 9.2.4

[dhalbert]

Somewhere between 9.2.4 and 9.2.5 some 32GB SD cards started failing with OSError: can't set 512 block size. I can reproduce this with a Micro Center card I have on PyPortal. EDIT: This is only on atmel-samd.

Test program:

import board
import sdcardio
import storage
import time

spi = board.SPI()
cs = board.SD_CS

print("mounting sd card...")
sdcard = sdcardio.SDCard(spi, cs)
vfs = storage.VfsFat(sdcard)
storage.mount(vfs, "/sd")
print("sd card mounted")

count = 0
while True:
    print("sleep 1", count)
    count += 1
    time.sleep(1)

[dhalbert]

Bisect shows this is due to

• SAMD51 SPI Secondary Mode #9385.

There are changes here:
https://github.com/adafruit/circuitpython/pull/9385/files#diff-89b411ec6aed2fc00953e3e6be4c8f704026b1bfd05d44b5732512fce9ae9f40
and here:
adafruit/samd-peripherals#46

Lots to look at here.

@Randall-Scharpf FYI something in #9385 is making some SD cards fail. sdcardio uses SPI.

One interesting thing is that while doing the bisect I hit several builds that just hung when trying to create the SDCard object, as opposed to giving the OSError: can't set 512 block size error.

[gh3262]

I wonder if this is a card size issue - 8 gb micro SD cards seem to work OK - I had two different no-brand cards that were recognized and mounted fine - the name brand Lexar 32gb cards don't work on the PyPortal and Titano although they work find on FruitJam and Metro RP2350.

[dhalbert]

I haven't re-tested smaller cards on a SAMD board like the PyPortal, but there's something definitely wrong on SAMD in particular.

One other difference between alpha.6 and alpha.7 is that we switched from gcc 13 to gcc 14 in #10386. It's possible this is a compiler problem, or perhaps a missing volatile or similar that only caused a problem due to the compiler switch. It's easy to test this.

[dhalbert]

One other difference between alpha.6 and alpha.7 is that we switched from gcc 13 to gcc 14 in #10386. It's possible this is a compiler problem, or perhaps a missing volatile or similar that only caused a problem due to the compiler switch. It's easy to test this.

Switching to gcc 13 for 10.0.1 did not help.