diff options
| author | Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> | 2022-11-08 15:19:49 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-11-25 19:45:52 +0300 |
| commit | a5eaad87bfca23b851a68f1f233ddd6f0bb25192 (patch) | |
| tree | 73bc18a5e08692fe3eab0423205425e19377a383 | |
| parent | f59f5a269ca5e43c567aca7f1f52500a0186e9b7 (diff) | |
| download | linux-a5eaad87bfca23b851a68f1f233ddd6f0bb25192.tar.xz | |
serial: 8250: Fall back to non-DMA Rx if IIR_RDI occurs
commit a931237cbea256aff13bb403da13a97b2d1605d9 upstream.
DW UART sometimes triggers IIR_RDI during DMA Rx when IIR_RX_TIMEOUT
should have been triggered instead. Since IIR_RDI has higher priority
than IIR_RX_TIMEOUT, this causes the Rx to hang into interrupt loop.
The problem seems to occur at least with some combinations of
small-sized transfers (I've reproduced the problem on Elkhart Lake PSE
UARTs).
If there's already an on-going Rx DMA and IIR_RDI triggers, fall
graciously back to non-DMA Rx. That is, behave as if IIR_RX_TIMEOUT had
occurred.
8250_omap already considers IIR_RDI similar to this change so its
nothing unheard of.
Fixes: 75df022b5f89 ("serial: 8250_dma: Fix RX handling")
Cc: <stable@vger.kernel.org>
Co-developed-by: Srikanth Thokala <srikanth.thokala@intel.com>
Signed-off-by: Srikanth Thokala <srikanth.thokala@intel.com>
Co-developed-by: Aman Kumar <aman.kumar@intel.com>
Signed-off-by: Aman Kumar <aman.kumar@intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221108121952.5497-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/serial/8250/8250_port.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index 7cdfc2458d36..7a15bb14194c 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -1869,6 +1869,10 @@ EXPORT_SYMBOL_GPL(serial8250_modem_status); static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir) { switch (iir & 0x3f) { + case UART_IIR_RDI: + if (!up->dma->rx_running) + break; + fallthrough; case UART_IIR_RX_TIMEOUT: serial8250_rx_dma_flush(up); fallthrough; |