diff options
Diffstat (limited to 'drivers/tty/serial/8250.c')
| -rw-r--r-- | drivers/tty/serial/8250.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/drivers/tty/serial/8250.c b/drivers/tty/serial/8250.c index a3f966b39862..295fd2d7c713 100644 --- a/drivers/tty/serial/8250.c +++ b/drivers/tty/serial/8250.c @@ -1641,6 +1641,7 @@ static irqreturn_t serial8250_interrupt(int irq, void *dev_id) struct irq_info *i = dev_id; struct list_head *l, *end = NULL; int pass_counter = 0, handled = 0; + static unsigned int tegra_spurious = 0; DEBUG_INTR("serial8250_interrupt(%d)...", irq); @@ -1674,6 +1675,26 @@ static irqreturn_t serial8250_interrupt(int irq, void *dev_id) handled = 1; end = NULL; + } else if ((up->port.type == PORT_TEGRA) && !handled) { + /* irq 68: nobody cared workaround */ + + /* The irq request flag sometimes does not get reset or is + * asserted immediately, but iir does not indicated this, if + * so we get here with iir set to 0xc1, i.e. no irq pending. */ + + /* Try enabling the transmit register empty interrupt, + * iir becomes 0xc2, irq gets de-asserted and ier is reverted + * by the regular code flow in the ISR. */ + tegra_spurious++; + /* Try this every 4096 spurious irq. */ + if ((tegra_spurious % 0x1000) == 0xfff) { + up->ier |= UART_IER_THRI; + serial_out(up, UART_IER, up->ier); + udelay(1); + handled = 1; + end = NULL; + } else if (end == NULL) + end = l; } else if (end == NULL) end = l; |