From 7a6fbc9a887193a1e9f8658703881c528040afbc Mon Sep 17 00:00:00 2001 From: Alexander Shiyan Date: Tue, 27 Mar 2012 12:22:49 +0400 Subject: [PATCH 1/3] ARM: clps711x: serial driver hungs are a result of call disable_irq within ISR Since 2.6.30-rc1 clps711x serial driver hungs system. This is a result of call disable_irq from ISR. synchronize_irq waits for end of interrupt and goes to infinite loop. This patch fix this problem. Signed-off-by: Alexander Shiyan Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/clps711x.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/tty/serial/clps711x.c b/drivers/tty/serial/clps711x.c index e6c3dbd781d6..836fe2731234 100644 --- a/drivers/tty/serial/clps711x.c +++ b/drivers/tty/serial/clps711x.c @@ -154,10 +154,9 @@ static irqreturn_t clps711xuart_int_tx(int irq, void *dev_id) port->x_char = 0; return IRQ_HANDLED; } - if (uart_circ_empty(xmit) || uart_tx_stopped(port)) { - clps711xuart_stop_tx(port); - return IRQ_HANDLED; - } + + if (uart_circ_empty(xmit) || uart_tx_stopped(port)) + goto disable_tx_irq; count = port->fifosize >> 1; do { @@ -171,8 +170,11 @@ static irqreturn_t clps711xuart_int_tx(int irq, void *dev_id) if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(port); - if (uart_circ_empty(xmit)) - clps711xuart_stop_tx(port); + if (uart_circ_empty(xmit)) { + disable_tx_irq: + disable_irq_nosync(TX_IRQ(port)); + tx_enabled(port) = 0; + } return IRQ_HANDLED; } From af6d17cdc8c89aeb3101f0d27cd32fc0592b40b2 Mon Sep 17 00:00:00 2001 From: Tomoya MORINAGA Date: Thu, 12 Apr 2012 10:47:50 +0900 Subject: [PATCH 2/3] pch_uart: Fix dma channel unallocated issue This driver anticipates pch_uart_verify_port() is not called during installation. However, actually pch_uart_verify_port() is called during installation. As a result, memory access violation occurs like below. 0. initial value: use_dma=0 1. starup() - dma channel is not allocated because use_dma=0 2. pch_uart_verify_port() - Set use_dma=1 3. UART processing acts DMA mode because use_dma=1 - memory access violation occurs! This patch fixes the issue. Solution: Whenever pch_uart_verify_port() is called and then dma channel is not allocated, the channel should be allocated. Signed-off-by: Tomoya MORINAGA Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/pch_uart.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c index bbbec4a74cfb..c2816f494807 100644 --- a/drivers/tty/serial/pch_uart.c +++ b/drivers/tty/serial/pch_uart.c @@ -1447,9 +1447,11 @@ static int pch_uart_verify_port(struct uart_port *port, __func__); return -EOPNOTSUPP; #endif - priv->use_dma = 1; priv->use_dma_flag = 1; dev_info(priv->port.dev, "PCH UART : Use DMA Mode\n"); + if (!priv->use_dma) + pch_request_dma(port); + priv->use_dma = 1; } return 0; From d3a7b83f865b46bb7b5e1ed18a129ce1af349db4 Mon Sep 17 00:00:00 2001 From: Julia Lawall Date: Thu, 19 Apr 2012 18:12:40 +0200 Subject: [PATCH 3/3] drivers/tty/amiserial.c: add missing tty_unlock tty_unlock is used on all other exits from the function. Signed-off-by: Julia Lawall Acked-by: Jiri Slaby Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/tty/amiserial.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/tty/amiserial.c b/drivers/tty/amiserial.c index 24145c30c9b0..6cc4358f68c1 100644 --- a/drivers/tty/amiserial.c +++ b/drivers/tty/amiserial.c @@ -1073,8 +1073,10 @@ static int set_serial_info(struct tty_struct *tty, struct serial_state *state, (new_serial.close_delay != port->close_delay) || (new_serial.xmit_fifo_size != state->xmit_fifo_size) || ((new_serial.flags & ~ASYNC_USR_MASK) != - (port->flags & ~ASYNC_USR_MASK))) + (port->flags & ~ASYNC_USR_MASK))) { + tty_unlock(); return -EPERM; + } port->flags = ((port->flags & ~ASYNC_USR_MASK) | (new_serial.flags & ASYNC_USR_MASK)); state->custom_divisor = new_serial.custom_divisor;