Support named SPI pins on Arduino Zero #11
Labels
Comments
jepler
added a commit
to jepler/circuitpython
that referenced
this issue
Nov 25, 2019
It's probably not the whole story, however, this fixes a crash observed
when bulk copying data to an nRF board using `dd`.
Basically, the call stack looked like this when resetting into safe mode:
#0 reset_into_safe_mode reason=reason@entry=GC_ALLOC_OUTSIDE_VM
#1 gc_alloc
.. #4 external_flash_write_block
.. adafruit#11 usb_background
adafruit#12 run_background_tasks
adafruit#13 common_hal_neopixel_write
.. adafruit#18 start_mp
i.e., during early startup, it is not okay yet to call allocation functions
like m_malloc_maybe that use the garbage collected heap. However,
nRF's neopixel_write (which already includes special handling to avoid
heap allocations for the status pixel!) can enter background tasks, which
do nearly arbitrary things including heap allocations.
We re-use the same test that switches from heap allocation to stack
allocation for the pattern buffer.
jepler
added a commit
to jepler/circuitpython
that referenced
this issue
Oct 1, 2020
It was incorrect to NULL out the pointer to our heap allocated buffer in `reset`, because subsequent to framebuffer_reset, but while the heap was still active, we could call `get_bufinfo` again, leading to a fresh allocation on the heap that is about to be destroyed. Typical stack trace: ``` #1 0x0006c368 in sharpdisplay_framebuffer_get_bufinfo #2 0x0006ad6e in _refresh_display #3 0x0006b168 in framebufferio_framebufferdisplay_background #4 0x00069d22 in displayio_background adafruit#5 0x00045496 in supervisor_background_tasks adafruit#6 0x000446e8 in background_callback_run_all adafruit#7 0x00045546 in supervisor_run_background_tasks_if_tick adafruit#8 0x0005b042 in common_hal_neopixel_write adafruit#9 0x00044c4c in clear_temp_status adafruit#10 0x000497de in spi_flash_flush_keep_cache adafruit#11 0x00049a66 in supervisor_external_flash_flush adafruit#12 0x00044b22 in supervisor_flash_flush adafruit#13 0x0004490e in filesystem_flush adafruit#14 0x00043e18 in cleanup_after_vm adafruit#15 0x0004414c in run_repl adafruit#16 0x000441ce in main ``` When this happened -- which was inconsistent -- the display would keep some heap allocation across reset which is exactly what we need to avoid. NULLing the pointer in reconstruct follows what RGBMatrix does, and that code is a bit more battle-tested anyway. If I had a motivation for structuring the SharpMemory code differently, I can no longer recall it. Testing performed: Ran my complicated calculator program over multiple iterations without observing signs of heap corruption. Closes: adafruit#3473
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Not a high priority but the Arduino Zero board config doesn't have SCK, MOSI, MISO pins like the feather board. Although not as common and easy to use it might be nice to support these as digital IO / named pins to be consistent. This might also mean SPI doesn't currently work on the Zero board (untested).
The text was updated successfully, but these errors were encountered: