sphinx-key: customize led loop stack size

these two previous commits bring the post-startup DRAM usage from
90k to 92k. I thought we were reducing stack sizes from 10k to
1.5k as in this commit, which would yield a similar delta on DRAM
usage, but I might be wrong here.

sphinx-key/src/btn.rs

@@ -5,7 +5,9 @@ mod periph;
 mod status;
 
 pub use crate::core::control::FlashPersister;
+use esp_idf_hal::gpio::Gpio0;
 use esp_idf_hal::gpio::Gpio9;
+use esp_idf_hal::peripheral::Peripheral;
 use esp_idf_hal::peripherals::Peripherals;
 use esp_idf_svc::nvs::EspDefaultNvsPartition;
 use esp_idf_svc::nvs::EspNvs;
@@ -22,17 +24,21 @@ const ID_LEN: usize = 12;
 
 fn main() -> anyhow::Result<()> {
     esp_idf_sys::link_patches();
-
     esp_idf_svc::log::EspLogger::initialize_default();
-
     thread::sleep(Duration::from_secs(1));
+    let mut peripherals = Peripherals::take().unwrap();
 
-    let peripherals = Peripherals::take().unwrap();
-    let pins = peripherals.pins;
-
-    let (led_tx, led_rx) = mpsc::channel::<Status>();
     // LED control thread
-    periph::led::led_control_loop(pins.gpio0, peripherals.rmt.channel0, led_rx);
+    let (mut led_tx, mut led_rx) = mpsc::channel::<Status>();
+    while let Err(e) = periph::led::led_control_loop(
+        unsafe { Gpio0::new() },
+        unsafe { peripherals.rmt.channel0.clone_unchecked() },
+        led_rx,
+    ) {
+        log::error!("unable to spawn led thread: {:?}", e);
+        thread::sleep(Duration::from_millis(1000));
+        (led_tx, led_rx) = mpsc::channel::<Status>();
+    }
 
     // BUTTON thread
     let default_nvs = EspDefaultNvsPartition::take()?;

sphinx-key/src/main.rs

@@ -14,7 +14,8 @@ use crate::periph::sd::{mount_sd_card, simple_fs_test};
 use crate::status::Status;
 
 use anyhow::Result;
-use esp_idf_hal::gpio::Gpio9;
+use esp_idf_hal::gpio::{Gpio0, Gpio9};
+use esp_idf_hal::peripheral::Peripheral;
 use esp_idf_hal::peripherals::Peripherals;
 use esp_idf_svc::nvs::EspDefaultNvsPartition;
 use esp_idf_sys as _; // If using the `binstart` feature of `esp-idf-sys`, always keep this module imported
@@ -31,17 +32,21 @@ fn main() -> Result<()> {
     // Temporary. Will disappear once ESP-IDF 4.4 is released, but for now it is necessary to call this function once,
     // or else some patches to the runtime implemented by esp-idf-sys might not link properly.
     esp_idf_sys::link_patches();
-
     esp_idf_svc::log::EspLogger::initialize_default();
-
     thread::sleep(Duration::from_secs(1));
+    let mut peripherals = Peripherals::take().unwrap();
 
-    let peripherals = Peripherals::take().unwrap();
-    let pins = peripherals.pins;
-
-    let (led_tx, led_rx) = mpsc::channel();
     // LED control thread
-    led_control_loop(pins.gpio0, peripherals.rmt.channel0, led_rx);
+    let (mut led_tx, mut led_rx) = mpsc::channel::<Status>();
+    while let Err(e) = led_control_loop(
+        unsafe { Gpio0::new() },
+        unsafe { peripherals.rmt.channel0.clone_unchecked() },
+        led_rx,
+    ) {
+        log::error!("unable to spawn led thread: {:?}", e);
+        thread::sleep(Duration::from_millis(1000));
+        (led_tx, led_rx) = mpsc::channel::<Status>();
+    }
 
     led_tx.send(Status::MountingSDCard).unwrap();
     println!("About to mount the sdcard...");
@@ -57,9 +62,7 @@ fn main() -> Result<()> {
     let flash_per = FlashPersister::new(default_nvs.clone());
     let flash_arc = Arc::new(Mutex::new(flash_per));
     // BUTTON thread
-    while let Err(e) =
-        button_loop(unsafe { Gpio9::new() }, led_tx.clone(), flash_arc.clone())
-    {
+    while let Err(e) = button_loop(unsafe { Gpio9::new() }, led_tx.clone(), flash_arc.clone()) {
         log::error!("unable to spawn button thread: {:?}", e);
         thread::sleep(Duration::from_millis(1000));
     }

sphinx-key/src/periph/led.rs

@@ -1,4 +1,5 @@
 use crate::status::Status;
+use anyhow::Result;
 use esp_idf_hal::rmt::config::TransmitConfig;
 use esp_idf_hal::rmt::{FixedLengthSignal, PinState, Pulse, TxRmtDriver};
 use esp_idf_hal::{gpio, rmt};
@@ -37,12 +38,17 @@ fn states() -> BTreeMap<Status, (Color, Time)> {
     s
 }
 
-pub fn led_control_loop(gpio0: gpio::Gpio0, channel0: rmt::CHANNEL0, rx: mpsc::Receiver<Status>) {
+pub fn led_control_loop(
+    gpio0: gpio::Gpio0,
+    channel0: rmt::CHANNEL0,
+    rx: mpsc::Receiver<Status>,
+) -> Result<()> {
     let config = TransmitConfig::new().clock_divider(1);
     let transmit = Arc::new(Mutex::new(
         TxRmtDriver::new(channel0, gpio0, &config).unwrap(),
     ));
-    thread::spawn(move || {
+    let builder = thread::Builder::new().stack_size(1500);
+    builder.spawn(move || {
         let mut led = Led::new(0x000001, 100);
         let states = states();
         loop {
@@ -55,7 +61,8 @@ pub fn led_control_loop(gpio0: gpio::Gpio0, channel0: rmt::CHANNEL0, rx: mpsc::R
             led.blink(transmit.clone());
             thread::sleep(Duration::from_millis(400));
         }
-    });
+    })?;
+    Ok(())
 }
 
 impl Led {