user/sven/linux.git/drivers/tty, branch v3.4.89

hvc: ensure hvc_init is only ever called once in hvc_console.c

2014-05-06T14:51:45Z

commit f76a1cbed18c86e2d192455f0daebb48458965f3 upstream. Commit 3e6c6f630a5282df8f3393a59f10eb9c56536d23 ("Delay creation of khcvd thread") moved the call of hvc_init from being a device_initcall into hvc_alloc, and used a non-null hvc_driver as indication of whether hvc_init had already been called. The problem with this is that hvc_driver is only assigned a value at the bottom of hvc_init, and so there is a window where multiple hvc_alloc calls can be in progress at the same time and hence try and call hvc_init multiple times. Previously the use of device_init guaranteed that hvc_init was only called once. This manifests itself as sporadic instances of two hvc_init calls racing each other, and with the loser of the race getting -EBUSY from tty_register_driver() and hence that virtual console fails: Couldn't register hvc console driver virtio-ports vport0p1: error -16 allocating hvc for port Here we add an atomic_t to guarantee we'll never run hvc_init twice. Cc: Rusty Russell Cc: Greg Kroah-Hartman Fixes: 3e6c6f630a52 ("Delay creation of khcvd thread") Reported-by: Jim Somerville Tested-by: Jim Somerville Signed-off-by: Paul Gortmaker Signed-off-by: Greg Kroah-Hartman

tty: n_gsm: Fix for modems with brk in modem status control

2014-02-22T18:32:45Z

commit 3ac06b905655b3ef2fd2196bab36e4587e1e4e4f upstream. 3GPP TS 07.10 states in section 5.4.6.3.7: "The length byte contains the value 2 or 3 ... depending on the break signal." The break byte is optional and if it is sent, the length is 3. In fact the driver was not able to work with modems that send this break byte in their modem status control message. If the modem just sends the break byte if it is really set, then weird things might happen. The code for deconding the modem status to the internal linux presentation in gsm_process_modem has already a big comment about this 2 or 3 byte length thing and it is already able to decode the brk, but the code calling the gsm_process_modem function in gsm_control_modem does not encode it and hand it over the right way. This patch fixes this. Without this fix if the modem sends the brk byte in it's modem status control message the driver will hang when opening a muxed channel. Signed-off-by: Lars Poeschel Signed-off-by: Greg Kroah-Hartman

serial: add support for 200 v3 series Titan card

2014-02-06T19:05:47Z

commit 48c0247d7b7bf58abb85a39021099529df365c4d upstream. Signed-off-by: Yegor Yefremov Signed-off-by: Greg Kroah-Hartman

tty/serial: at91: Handle shutdown more safely

2014-02-06T19:05:47Z

commit 0cc7c6c7916b1b6f34350ff1473b80b9f7e459c0 upstream. Interrupts were being cleaned up late in the shutdown handler, it is possible that an interrupt can occur and schedule a tasklet that runs after the port is cleaned up. There is a null dereference due to this race condition with the following stacktrace: [] (atmel_tasklet_func+0x514/0x814) from [] (tasklet_action+0x70/0xa8) [] (tasklet_action+0x70/0xa8) from [] (__do_softirq+0x90/0x144) [] (__do_softirq+0x90/0x144) from [] (irq_exit+0x40/0x4c) [] (irq_exit+0x40/0x4c) from [] (handle_IRQ+0x64/0x84) [] (handle_IRQ+0x64/0x84) from [] (__irq_svc+0x40/0x50) [] (__irq_svc+0x40/0x50) from [] (atmel_rx_dma_release+0x88/0xb8) [] (atmel_rx_dma_release+0x88/0xb8) from [] (atmel_shutdown+0x104/0x160) [] (atmel_shutdown+0x104/0x160) from [] (uart_port_shutdown+0x2c/0x38) Signed-off-by: Marek Roszko Acked-by: Leilei Zhao Signed-off-by: Nicolas Ferre Signed-off-by: Greg Kroah-Hartman

TTY: pmac_zilog, check existence of ports in pmz_console_init()

2014-01-08T17:42:10Z

commit dc1dc2f8a5dd863bf2e79f338fc3ae29e99c683a upstream. When booting a multi-platform m68k kernel on a non-Mac with "console=ttyS0" on the kernel command line, it crashes with: Unable to handle kernel NULL pointer dereference at virtual address (null) Oops: 00000000 PC: [<0013ad28>] __pmz_startup+0x32/0x2a0 ... Call Trace: [<002c5d3e>] pmz_console_setup+0x64/0xe4 The normal tty driver doesn't crash, because init_pmz() checks pmz_ports_count again after calling pmz_probe(). In the serial console initialization path, pmz_console_init() doesn't do this, causing the driver to crash later. Add a check for pmz_ports_count to fix this. Signed-off-by: Geert Uytterhoeven Cc: Finn Thain Cc: Benjamin Herrenschmidt Signed-off-by: Greg Kroah-Hartman

powerpc/hvsi: Increase handshake timeout from 200ms to 400ms.

2013-09-08T04:58:14Z

commit d220980b701d838560a70de691b53be007e99e78 upstream. This solves a problem observed in kexec'ed kernel where 200ms timeout is too short and bootconsole fails to initialize. Console did eventually become workable but much later into the boot process. Observed timeout was around 260ms, but I decided to make it a little bigger for more reliability. This has been tested on Power7 machine with Petitboot as a primary bootloader and PowerNV firmware. Signed-off-by: Eugene Surovegin Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Greg Kroah-Hartman

serial/mxs-auart: increase time to wait for transmitter to become idle

2013-08-11T22:38:41Z

commit 079a036f4283e2b0e5c26080b8c5112bc0cc1831 upstream. Without this patch the driver waits ~1 ms for the UART to become idle. At 115200n8 this time is (theoretically) enough to transfer 11.5 characters (= 115200 bits/s / (10 Bits/char) * 1ms). As the mxs-auart has a fifo size of 16 characters the clock is gated too early. The problem is worse for lower baud rates. This only happens to really shut down the transmitter in the middle of a transfer if /dev/ttyAPPx isn't opened in userspace (e.g. by a getty) but was at least once (because the bootloader doesn't disable the transmitter). So increase the timeout to 20 ms which should be enough for 9600n8, too. Moreover skip gating the clock if the timeout is elapsed. Signed-off-by: Uwe Kleine-König Signed-off-by: Greg Kroah-Hartman

serial/mxs-auart: fix race condition in interrupt handler

2013-08-11T22:38:41Z

commit d970d7fe65adff5efe75b4a73c4ffc9be57089f7 upstream. The handler needs to ack the pending events before actually handling them. Otherwise a new event might come in after it it considered non-pending or handled and is acked then without being handled. So this event is only noticed when the next interrupt happens. Without this patch an i.MX28 based machine running an rt-patched kernel regularly hangs during boot. Signed-off-by: Uwe Kleine-König Signed-off-by: Greg Kroah-Hartman

Revert "serial: 8250_pci: add support for another kind of NetMos Technology PCI 9835 Multi-I/O Controller"

2013-07-13T18:03:41Z

commit 828c6a102b1f2b8583fadc0e779c46b31d448f0b upstream. This reverts commit 8d2f8cd424ca0b99001f3ff4f5db87c4e525f366. As reported by Stefan, this device already works with the parport_serial driver, so the 8250_pci driver should not also try to grab it as well. Reported-by: Stefan Seyfried Cc: Wang YanQing Signed-off-by: Greg Kroah-Hartman

pch_uart: fix a deadlock when pch_uart as console

2013-07-03T17:59:05Z

commit 384e301e3519599b000c1a2ecd938b533fc15d85 upstream. When we use pch_uart as system console like 'console=ttyPCH0,115200', then 'send break' to it. We'll encounter the deadlock on a cpu/core, with interrupts disabled on the core. When we happen to have all irqs affinity to cpu0 then the deadlock on cpu0 actually deadlock whole system. In pch_uart_interrupt, we have spin_lock_irqsave(&priv->lock, flags) then call pch_uart_err_ir when break is received. Then the call to dev_err would actually call to pch_console_write then we'll run into another spin_lock(&priv->lock), with interrupts disabled. So in the call sequence lead by pch_uart_interrupt, we should be carefully to call functions that will 'print message to console' only in case the uart port is not being used as serial console. Signed-off-by: Liang Li Cc: Yijing Wang Signed-off-by: Greg Kroah-Hartman