The interrupt clearing code in mpsc_sdma_intr_ack() mistakenly clears the interrupt for both controllers instead of just the one its supposed to. This can result in the other controller appearing to hang because its interrupt was effectively lost. So, don't clear the interrupt cause bits for both MPSC controllers when clearing the interrupt for one of them. Just clear the one that is supposed to be cleared. Signed-off-by: Jay Lubomirski Acked-by: Mark A. Greer Signed-off-by: Andrew Morton Signed-off-by: Chris Wright Signed-off-by: Greg Kroah-Hartman --- drivers/serial/mpsc.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/drivers/serial/mpsc.c b/drivers/serial/mpsc.c index 3d2fcc5..64ed5ef 100644 --- a/drivers/serial/mpsc.c +++ b/drivers/serial/mpsc.c @@ -502,7 +502,8 @@ mpsc_sdma_intr_ack(struct mpsc_port_info *pi) if (pi->mirror_regs) pi->shared_regs->SDMA_INTR_CAUSE_m = 0; - writel(0, pi->shared_regs->sdma_intr_base + SDMA_INTR_CAUSE); + writeb(0x00, pi->shared_regs->sdma_intr_base + SDMA_INTR_CAUSE + + pi->port.line); return; } -- 1.5.2.4 -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/