linux-kernel - [PATCH] PM: Fixes warning on suspend errors

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Message-ID: <B85A65D85D7EB246BE421B3FB0FBB59301DE0DC96A@dbde02.ent.ti.com>
Date:	Tue, 27 Oct 2009 17:31:30 +0530
From:	"Dasgupta, Romit" <romit@...com>
To:	"Hilman, Kevin" <khilman@...com>, "rjw@...k.pl" <rjw@...k.pl>
CC:	"linux-pm@...ts.linux-foundation.org" 
	<linux-pm@...ts.linux-foundation.org>,
	"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH] PM: Fixes warning on suspend errors

Hi,
     I get the following errors when I choose devices in /sys/power/pm_test. It also shows that if 'dpm_suspend_start' fails somewhere down the line then the kernel does not reset the 'transition_started' variable and we can get warning similar to below. IMHO 'dpm_resume_noirq' is not the right place for setting this variable. Please see the patch below which fixes the issue.

Thanks,
-Romit


# [  113.713958] mmcblk0: mmc1:0001 STM16G 14.8 GiB
[  113.718902]  mmcblk0: unknown partition table
[  113.745574] ------------[ cut here ]------------
[  113.751525] WARNING: at drivers/base/power/main.c:98 device_pm_add+0x94/0xdc()
[  113.758819] Device: bdi
[  113.758819] Parentless device registered during a PM transaction
[  113.773071] Modules linked in:
[  113.776214] [<c002b87c>] (unwind_backtrace+0x0/0xdc) from [<c004ff58>] (warn_slowpath_common+0x48/0x60)
[  113.785705] [<c004ff58>] (warn_slowpath_common+0x48/0x60) from [<c004ffa8>] (warn_slowpath_fmt+0x24/0x30)
[  113.799896] [<c004ffa8>] (warn_slowpath_fmt+0x24/0x30) from [<c01b36b8>] (device_pm_add+0x94/0xdc)
[  113.808990] [<c01b36b8>] (device_pm_add+0x94/0xdc) from [<c01ad9bc>] (device_add+0x3a8/0x534)
[  113.817565] [<c01ad9bc>] (device_add+0x3a8/0x534) from [<c01adbd8>] (device_create_vargs+0x78/0xa8)
[  113.829650] [<c01adbd8>] (device_create_vargs+0x78/0xa8) from [<c0090a9c>] (bdi_register+0x3c/0x154)
[  113.839263] [<c0090a9c>] (bdi_register+0x3c/0x154) from [<c0090bd4>] (bdi_register_dev+0x20/0x28)
[  113.851348] [<c0090bd4>] (bdi_register_dev+0x20/0x28) from [<c0173b98>] (add_disk+0xe4/0x124)
[  113.859954] [<c0173b98>] (add_disk+0xe4/0x124) from [<c01e6b54>] (mmc_blk_probe+0x250/0x288)
[  113.870513] [<c01e6b54>] (mmc_blk_probe+0x250/0x288) from [<c01e14d4>] (mmc_bus_probe+0x18/0x1c)
[  113.879394] [<c01e14d4>] (mmc_bus_probe+0x18/0x1c) from [<c01af97c>] (driver_probe_device+0xa0/0x14c)
[  113.893890] [<c01af97c>] (driver_probe_device+0xa0/0x14c) from [<c01aef44>] (bus_for_each_drv+0x44/0x80)
[  113.905609] [<c01aef44>] (bus_for_each_drv+0x44/0x80) from [<c01afb60>] (device_attach+0x50/0x68)
[  113.914550] [<c01afb60>] (device_attach+0x50/0x68) from [<c01aed94>] (bus_probe_device+0x24/0x40)
[  113.925170] [<c01aed94>] (bus_probe_device+0x24/0x40) from [<c01ad9f0>] (device_add+0x3dc/0x534)
[  113.934082] [<c01ad9f0>] (device_add+0x3dc/0x534) from [<c01e1688>] (mmc_add_card+0xcc/0x118)
[  113.945251] [<c01e1688>] (mmc_add_card+0xcc/0x118) from [<c01e2408>] (mmc_attach_mmc+0xdc/0x13c)
[  113.954132] [<c01e2408>] (mmc_attach_mmc+0xdc/0x13c) from [<c01e12f0>] (mmc_rescan+0x2b0/0x2e8)
[  113.964874] [<c01e12f0>] (mmc_rescan+0x2b0/0x2e8) from [<c0060840>] (worker_thread+0x16c/0x218)
[  113.973693] [<c0060840>] (worker_thread+0x16c/0x218) from [<c0063d88>] (kthread+0x7c/0x84)
[  113.986694] [<c0063d88>] (kthread+0x7c/0x84) from [<c0026ea0>] (kernel_thread_exit+0x0/0x8)
[  113.995147] ---[ end trace aaa7bf5becc572f5 ]---




Fixes the location where we decide that our power transition is complete.
Signed-off-by: Romit Dasgupta <romit@...com>
---
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index e0dc407..6b9e991 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -365,7 +365,6 @@ void dpm_resume_noirq(pm_message_t state)
 	struct device *dev;
 
 	mutex_lock(&dpm_list_mtx);
-	transition_started = false;
 	list_for_each_entry(dev, &dpm_list, power.entry)
 		if (dev->power.status > DPM_OFF) {
 			int error;
@@ -529,6 +528,7 @@ static void dpm_complete(pm_message_t state)
 		put_device(dev);
 	}
 	list_splice(&list, &dpm_list);
+	transition_started = false;
 	mutex_unlock(&dpm_list_mtx);
 }

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