On 12/03/2016 02:58 AM, Nikita Yushchenko wrote:
Problem found via lockdep:
- lpuart_set_termios() calls del_timer_sync(&sport->lpuart_timer) while
holding sport->port.lock
- sport->lpuart_timer routine is lpuart_timer_func() that calls
lpuart_copy_rx_to_tty() that acquires same lock.
To fix, move Rx DMA stopping out of lock, as it already is in other places
in the same file.
While at it, also make Rx DMA start/stop code to look the same is in
other places in the same file.
Yeah I saw that too, never really came around to look closer into it.
Thanks for looking into it.
You removed the check whether there was an old configuration, I think
the idea of that was that we only resize DMA if it was configured
differently before...
Per my code reading, checking for sport->lpuart_dma_rx_use should be
enough, this flag will be set only if DMA was previously enabled,
The check is to make sure the reconfiguration of DMA is done only when
the baudrate is altered.
--
Bhuvan
+ if (sport->lpuart_dma_rx_use) {
+ if (!lpuart_start_rx_dma(sport)) {
sport->lpuart_dma_rx_use = true;
No need to set to true here, it is guaranteed to be true at this point.
I've seen this... However elsewhere in this file (namely in
lpuart_resume(), in very similar situation, code is exactly the same,
i.e. it sets sport->lpuart_dma_rx_use in both clauses. I thought it
could be for a reason (i.e. for readability).
Nikita
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