Fixes uartAvailable() in case UART_READ_RX_FIFO is set #5541
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Thank you for the PR, @SuGlider. Do interrupts also have to be turned off? For example, what happens if |
atanisoft
reviewed
Aug 14, 2021
cores/esp32/esp32-hal-uart.c
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| return (uxQueueMessagesWaiting(uart->queue) + uart->dev->status.rxfifo_cnt) ; | ||
| UART_MUTEX_UNLOCK(); |
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this line will never be called and the lock will potentially be left locked. You will need to store the value in a temporary variable and unlock prior to return.
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Absolutely right!
esp32-hal-uart.c is being refactored.
For the matter UART_READ_RX_FIFO is unset by default, thus this part of the code isn't used in 2.0.0.
Closing this PR in favor of the UART code refactoring.
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Summary
Fixes #5512
In version 2.0.0, in case UART_READ_RX_FIFO is set, a race condition may happen causing the result of uartAvailable() to fail.
If two tasks read the same UART, uartAvailable() may be preempted right when the sum is being executed, generating a sporadic failed result.
Impact
Fixes the specific condition detailed in issue #5512