From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933647Ab1KJDUB (ORCPT ); Wed, 9 Nov 2011 22:20:01 -0500 Received: from cantor2.suse.de ([195.135.220.15]:41554 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933607Ab1KJDTx (ORCPT ); Wed, 9 Nov 2011 22:19:53 -0500 X-Mailbox-Line: From gregkh@clark.kroah.org Wed Nov 9 13:27:01 2011 Message-Id: <20111109212701.734121932@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Wed, 09 Nov 2011 13:25:36 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Ning Jiang Subject: [014/262] serial-core: power up uart port early before we do set_termios when resuming In-Reply-To: <20111109212847.GA20838@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ning Jiang commit 94abc56f4d90f289ea32a0a11d3577fcd8cb28fb upstream. The following patch removed uart_change_pm() in uart_resume_port(): commit 5933a161abcb8d83a2c145177f48027c3c0a8995 Author: Yin Kangkai serial-core: reset the console speed on resume It will break the pxa serial driver when the system resumes from suspend mode as it will try to set baud rate divider register in set_termios but with clock off. The register value can not be set correctly on some platform if the clock is disabled. The pxa driver will check the value and report the following warning: ------------[ cut here ]------------ WARNING: at drivers/tty/serial/pxa.c:545 serial_pxa_set_termios+0x1dc/0x250() Modules linked in: [] (unwind_backtrace+0x0/0xf0) from [] (warn_slowpath_common+0x4c/0x64) [] (warn_slowpath_common+0x4c/0x64) from [] (warn_slowpath_null+0x18/0x1c) [] (warn_slowpath_null+0x18/0x1c) from [] (serial_pxa_set_termios+0x1dc/0x250) [] (serial_pxa_set_termios+0x1dc/0x250) from [] (uart_resume_port+0x128/0x2dc) [] (uart_resume_port+0x128/0x2dc) from [] (serial_pxa_resume+0x18/0x24) [] (serial_pxa_resume+0x18/0x24) from [] (platform_pm_resume+0x40/0x4c) [] (platform_pm_resume+0x40/0x4c) from [] (pm_op+0x68/0xb4) [] (pm_op+0x68/0xb4) from [] (device_resume+0xb0/0xec) [] (device_resume+0xb0/0xec) from [] (dpm_resume+0xe0/0x194) [] (dpm_resume+0xe0/0x194) from [] (dpm_resume_end+0xc/0x18) [] (dpm_resume_end+0xc/0x18) from [] (suspend_devices_and_enter+0x16c/0x1ac) [] (suspend_devices_and_enter+0x16c/0x1ac) from [] (enter_state+0xac/0xdc) [] (enter_state+0xac/0xdc) from [] (state_store+0xa0/0xbc) [] (state_store+0xa0/0xbc) from [] (kobj_attr_store+0x18/0x1c) [] (kobj_attr_store+0x18/0x1c) from [] (sysfs_write_file+0x108/0x140) [] (sysfs_write_file+0x108/0x140) from [] (vfs_write+0xac/0x134) [] (vfs_write+0xac/0x134) from [] (sys_write+0x3c/0x68) [] (sys_write+0x3c/0x68) from [] (ret_fast_syscall+0x0/0x2c) ---[ end trace 88289eceb4675b04 ]--- This patch fix the problem by adding the power on opertion back for uart console when console_suspend_enabled is true. Signed-off-by: Ning Jiang Tested-by: Mayank Rana Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/serial_core.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -2003,6 +2003,8 @@ int uart_resume_port(struct uart_driver if (port->tty && port->tty->termios && termios.c_cflag == 0) termios = *(port->tty->termios); + if (console_suspend_enabled) + uart_change_pm(state, 0); uport->ops->set_termios(uport, &termios, NULL); if (console_suspend_enabled) console_start(uport->cons);