From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Govindraj.R" Subject: [PATCH v3 05/12] OMAP: Serial: Hold console lock for console usage. Date: Wed, 8 Jun 2011 16:53:07 +0530 Message-ID: <1307532194-13039-6-git-send-email-govindraj.raja@ti.com> References: <1307532194-13039-1-git-send-email-govindraj.raja@ti.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from comal.ext.ti.com ([198.47.26.152]:40236 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751277Ab1FHLXm (ORCPT ); Wed, 8 Jun 2011 07:23:42 -0400 In-Reply-To: <1307532194-13039-1-git-send-email-govindraj.raja@ti.com> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: linux-omap@vger.kernel.org, linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Tony Lindgren , Kevin Hilman , "Govindraj.R" Acquire console lock before enabling and writing to console-uart to avoid any recursive prints from console write. for ex: --> printk --> uart_console_write --> get_sync --> printk from omap_device enable --> uart_console write Use RPM_SUSPENDING check to avoid below scenario during bootup As during bootup console_lock is not available. --> uart_add_one_port --> console_register --> console_lock --> console_unlock --> call_console_drivers (here yet console_lock is not released) --> uart_console_write Acked-by: Alan Cox Signed-off-by: Govindraj.R --- drivers/tty/serial/omap-serial.c | 20 +++++++++++++++++++- 1 files changed, 19 insertions(+), 1 deletions(-) diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c index 897416f..ee94291 100644 --- a/drivers/tty/serial/omap-serial.c +++ b/drivers/tty/serial/omap-serial.c @@ -1008,7 +1008,22 @@ serial_omap_console_write(struct console *co, const char *s, struct uart_omap_port *up = serial_omap_console_ports[co->index]; unsigned long flags; unsigned int ier; - int locked = 1; + int console_lock = 0, locked = 1; + + if (console_trylock()) + console_lock = 1; + + /* + * If console_lock is not available and we are in suspending + * state then we can avoid the console usage scenario + * as this may introduce recursive prints. + * Basically this scenario occurs during boot while + * printing debug bootlogs. + */ + + if (!console_lock && + up->pdev->dev.power.runtime_status == RPM_SUSPENDING) + return; local_irq_save(flags); if (up->port.sysrq) @@ -1044,6 +1059,9 @@ serial_omap_console_write(struct console *co, const char *s, if (up->msr_saved_flags) check_modem_status(up); + if (console_lock) + console_unlock(); + serial_omap_port_disable(up); if (locked) spin_unlock(&up->port.lock); -- 1.7.0.4