forked from Minki/linux
Revert "serial: imx: always wake up the processes in the TX callback"
This reverts commit2ad28e3efe
. Instead of always wake up write_wait process in TX callback, TX callback should call imx_dma_tx() again, and let imx_dma_tx transfer the remaining data in circle buffer. The issue with commit2ad28e3
is, in case there is remaining data in circle buffer, but no process is waiting on write_wait queue, then as no following uart_write() will be called after uart_write_wakeup(), thus cause data loss. Moreover according to Documentation/serial/driver, uart_write_wakeup() should be called in case the transmit buffer have dropped below a threshold. Signed-off-by: Jiada Wang <jiada_wang@mentor.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -516,6 +516,7 @@ static void dma_tx_callback(void *data)
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spin_unlock_irqrestore(&sport->port.lock, flags);
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if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
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uart_write_wakeup(&sport->port);
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if (waitqueue_active(&sport->dma_wait)) {
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