The RS-485 tx_idle_num block in esp_setup() ends in a bare "else" that
binds to the next statement, which is now leave_critical_section(). On
an RS-485 port esp_setup() therefore returns with interrupts disabled.
uart_open() hides this behind its own critical section, but a
tcsetattr() that changes the line settings calls esp_setup() through
TCSETS and leaves the calling task running with interrupts off. On an
ESP32-C3 the system tick stops advancing in that task.
Assisted-by: Claude:claude-opus-5-5
Signed-off-by: Erik Englund <erik.englund@gmail.com>
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