sergiotarxz/nuttx
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

imxrt:Serial Do not wait on TXDMA semaphore

Browse Source 
If using flow control with a high CTS the thread may be
    blocked forever on the second transmit attempt due to waiting
    on the txdma semaphore.  The calling thread can then never
    make progress and release any resources it has taken, thus
    may cause a deadlock in other parts of the system.

    The implementation differs in behavior from interrupt-driven
    TX. It should not implicitly wait on a taken semaphore but
    return immediately and let the upper layers decide on what to
    do next.
This commit is contained in:
David Sidrane 2023-11-10 01:29:25 -08:00 committed by Xiang Xiao
parent 63182d43b9
commit 54b4cd3bf3
1 changed files with 5 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
arch/arm/src/imxrt/imxrt_serial.c
View File

@ -2535,9 +2535,12 @@ static void imxrt_dma_txavailable(struct uart_dev_s *dev)
/* Only send when the DMA is idle */
nxsem_wait(&priv->txdmasem);
int rv = nxsem_trywait(&priv->txdmasem);
uart_xmitchars_dma(dev);
if (rv == 0)
{
uart_xmitchars_dma(dev);
}
}
#endif