diff options
| author | Maciej W. Rozycki <macro@linux-mips.org> | 2016-01-30 12:11:46 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-02-07 10:13:30 +0300 |
| commit | fff21fac75ccebacd29fc16b56a46a124359917a (patch) | |
| tree | 9a311ac2a5a74f975e8f8bf8f8c17f2d95b036fd | |
| parent | bdc5f300958062a766518b81d5378f837149d5c1 (diff) | |
| download | linux-fff21fac75ccebacd29fc16b56a46a124359917a.tar.xz | |
serial: zs: Fix a transmit lockup in console output
Transmit interrupts are disabled and the transmit buffer drained in the
course of console output so that polled transmission is possible. That
however causes a lost transmit interrupt as the TxIP bit in RR3 is only
set on a transmit buffer full-to-empty transition and then iff transmit
interrupts are enabled at the same time. Consequently if console output
disturbs a regular transmission in progress, the TxIP bit is never set
again and the transmission locks up waiting for a transmit interrupt.
Fix the problem by restarting transmission manually rather than waiting
for a transmit interrupt that will never happen.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/serial/zs.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/tty/serial/zs.c b/drivers/tty/serial/zs.c index 2b65bb7ffb8a..eeefd76a30da 100644 --- a/drivers/tty/serial/zs.c +++ b/drivers/tty/serial/zs.c @@ -1181,6 +1181,10 @@ static void zs_console_write(struct console *co, const char *s, if (txint & TxINT_ENAB) { zport->regs[1] |= TxINT_ENAB; write_zsreg(zport, R1, zport->regs[1]); + + /* Resume any transmission as the TxIP bit won't be set. */ + if (!zport->tx_stopped) + zs_raw_transmit_chars(zport); } spin_unlock_irqrestore(&scc->zlock, flags); } |