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| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2014-09-29 22:06:40 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-11-06 06:05:13 +0300 |
| commit | b220282156440a62d5e9e58c0aade0f0daaa374c (patch) | |
| tree | e31389bd47f80f52758b0a52da63aa02e46b46cf /drivers/tty/serial/8250/8250.h | |
| parent | 61929cf0169d91366fd3f30d6ee60681b037bc19 (diff) | |
| download | linux-b220282156440a62d5e9e58c0aade0f0daaa374c.tar.xz | |
tty: serial: 8250_dma: handle error on TX submit
Right now it is possible that serial8250_tx_dma() fails and returns
-EBUSY. The caller (serial8250_start_tx()) will then enable
UART_IER_THRI which will generate an interrupt once the TX FIFO is
empty.
In serial8250_handle_irq() nothing will happen because up->dma is set
and so serial8250_tx_chars() won't be invoked. We end up with plenty of
interrupts and some "too much work for irq" output.
This patch introduces dma_tx_err in struct uart_8250_port to signal that
the last invocation of serial8250_tx_dma() failed so we can fill the TX
FIFO manually. Should the next invocation of serial8250_start_tx()
succeed then the dma_tx_err flag along with the THRI bit is removed and
DMA only usage may continue.
Reviewed-by: Tony Lindgren <tony@atomide.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial/8250/8250.h')
| -rw-r--r-- | drivers/tty/serial/8250/8250.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h index cb51be55989e..2292a4202425 100644 --- a/drivers/tty/serial/8250/8250.h +++ b/drivers/tty/serial/8250/8250.h @@ -41,6 +41,7 @@ struct uart_8250_dma { size_t tx_size; unsigned char tx_running:1; + unsigned char tx_err: 1; }; struct old_serial_port { |