Re: Unbalanced IRQ wake disable during resume from static suspend

Govindraj
2010-12-03T11:21:04Z

On Fri, Dec 3, 2010 at 4:38 PM, Santosh Shilimkar
<santosh.shilimkar@ti.com> wrote:
>> -----Original Message-----
>> From: Paul Walmsley [mailto:paul@pwsan.com]
>> Sent: Friday, December 03, 2010 3:53 PM
>> To: Santosh Shilimkar
>> Cc: linux-omap@vger.kernel.org; Govindraj; khilman@deeprootsystems.com
>> Subject: RE: Unbalanced IRQ wake disable during resume from static
> suspend
>>
>> Hello Santosh
>>
>> On Thu, 2 Dec 2010, Santosh Shilimkar wrote:
>>
>> > Just a wild guess here but is this because the 'set_wake' is
>> > not setup and then fw might be returning some error whenever
>> > driver invoke this API as part of enable_irq_wake() callback
>> >
>> > If that being the case, below patch might might help. Can
>> > somebody try this out ?
>>
>> This patch might remove the warnings, but I doubt that it solves the
> root
>> cause.  In any case, it doesn't seem correct to unconditionally return 0
>> (success) from an omap_irq_wake() function, given that the OMAP INTC has
>> no functionality in this regard.
>>
>> The real problem appears to be in drivers/serial/serial_core.c.
>> uart_suspend_port() doesn't check the return value of enable_irq_wake().
>> Seems to me that it needs to save that return value somewhere and not
>> bother calling disable_irq_wake() in uart_resume_port() if
>> enable_irq_wake() returned an error.
>>
>> That's the patch that I'd suggest that you guys put together and send to
>> the Linux serial people.
>>
> You are right Paul. This will actually fix the broken driver rather than
> masking it. Will spin a patch for the same
>

Hi Santosh/Paul,

How about this patch?
[Tested on 3630SDP

---
Regards,
Govindraj.R

From cb4e79a645b530f83f55d801ab054cc438ada0dd Mon Sep 17 00:00:00 2001
From: Govindraj.R <govindraj.raja@ti.com>
Date: Fri, 3 Dec 2010 16:42:14 +0530
Subject: [PATCH] Serial: Unbalanced IRQ wake disable during resume
from static suspend

Check for return status for enable_irq_wake if irq_wake
interface is not available then during resume unconditional
disabling of irq_wake can throw below warning.

------------[ cut here ]------------
WARNING: at kernel/irq/manage.c:382 set_irq_wake+0x80/0xe4()
Unbalanced IRQ 72 wake disable
Modules linked in:
[<c0062a28>] (unwind_backtrace+0x0/0xec) from [<c0092260>]
(warn_slowpath_common+0x4c/0x64)
[<c0092260>] (warn_slowpath_common+0x4c/0x64) from [<c00922f8>]
(warn_slowpath_fmt+0x2c/0x3c
[<c00922f8>] (warn_slowpath_fmt+0x2c/0x3c) from [<c00d3238>]
(set_irq_wake+0x80/0xe4)
[<c00d3238>] (set_irq_wake+0x80/0xe4) from [<c029dd60>]
(uart_resume_port+0x84/0x248)
[<c029dd60>] (uart_resume_port+0x84/0x248) from [<c02a2338>]
(serial_omap_resume+0x20/0x2c)
[<c02a2338>] (serial_omap_resume+0x20/0x2c) from [<c02a92d4>]
(platform_pm_resume+0x48/0x54)
[<c02a92d4>] (platform_pm_resume+0x48/0x54) from [<c02abd1c>]
(pm_op+0x6c/0xac)
[<c02abd1c>] (pm_op+0x6c/0xac) from [<c02ac0fc>]
(device_resume+0x58/0x10c)
[<c02ac0fc>] (device_resume+0x58/0x10c) from [<c02ac2ec>]
(dpm_resume_end+0xf4/0x360)
[<c02ac2ec>] (dpm_resume_end+0xf4/0x360) from [<c00cf58c>]
(suspend_devices_and_enter+0x1ac/0x200)
[<c00cf58c>] (suspend_devices_and_enter+0x1ac/0x200) from [<c00cf6c0>]
(enter_state+0xe0/0x138)
[<c00cf6c0>] (enter_state+0xe0/0x138) from [<c00ced18>]
(state_store+0x90/0xb8)
[<c00ced18>] (state_store+0x90/0xb8) from [<c0243b98>]
(kobj_attr_store+0x18/0x1c)
[<c0243b98>] (kobj_attr_store+0x18/0x1c) from [<c0176128>]
(sysfs_write_file+0x10c/0x144)
[<c0176128>] (sysfs_write_file+0x10c/0x144) from [<c0125528>]
(vfs_write+0xac/0x134)
[<c0125528>] (vfs_write+0xac/0x134) from [<c012565c>]
(sys_write+0x3c/0x68)
[<c012565c>] (sys_write+0x3c/0x68) from [<c005bb00>]
(ret_fast_syscall+0x0/0x3c)
---[ end trace 19fe50b7b47ba94f ]---

Thus add a flag to check the return status for irq_wake
based on flag disable the irq_wake

Signed-off-by: Govindraj.R <govindraj.raja@ti.com>
---
drivers/serial/serial_core.c | 6 ++++--
include/linux/serial_core.h | 1 +
2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index cd85112..0466815 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -1990,7 +1990,8 @@ int uart_suspend_port(struct uart_driver *drv,
struct uart_port *uport)

tty_dev = device_find_child(uport->dev, &match, serial_match_port);
if (device_may_wakeup(tty_dev)) {
- enable_irq_wake(uport->irq);
+ if (!enable_irq_wake(uport->irq))
+ uport->irq_wake = 1;
put_device(tty_dev);
mutex_unlock(&port->mutex);
return 0;
@@ -2056,7 +2057,8 @@ int uart_resume_port(struct uart_driver *drv,
struct uart_port *uport)

tty_dev = device_find_child(uport->dev, &match, serial_match_port);
if (!uport->suspended && device_may_wakeup(tty_dev)) {
- disable_irq_wake(uport->irq);
+ if (uport->irq_wake)
+ disable_irq_wake(uport->irq);
mutex_unlock(&port->mutex);
return 0;
}
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 295e898..88e73c3 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -359,6 +359,7 @@ struct uart_port {
struct device *dev; /* parent device */
unsigned char hub6; /* this should be in the 8250 driver */
unsigned char suspended;
+ unsigned char irq_wake; /* Irq_wakeup Available */
unsigned char unused[2];
void *private_data; /* generic platform data pointer */
};
--
1.7.1
--
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