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Revert "clocksource: sh_tmu: Runtime PM support" 

This reverts commit 1b842e91fe.

There is a fundamental ordering race between the early and late probe
paths and the runtime PM tie-in that results in __pm_runtime_resume()
attempting to take a lock that hasn't been initialized yet (which by
proxy also suggests that pm_runtime_init() hasn't yet been run on the
device either, making the entire thing unsafe) -- resulting in instant
death on SMP or on UP with spinlock debugging enabled:

	 sh_tmu.0: used for clock events
	 sh_tmu.0: used for periodic clock events
	BUG: spinlock trylock failure on UP on CPU#0, swapper/0
	 lock: 804db198, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
	...

Revert it for now until the ordering issues can be resolved, or we can get
some more help from the runtime PM framework to make this possible.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Paul Mundt 2011-05-31 15:23:20 +09:00
parent db7eba292e
commit d4905ce38c
1 changed files with 2 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/clocksource/sh_tmu.c
View File

@ -25,7 +25,6 @@
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/pm_runtime.h>
#include <linux/irq.h>
#include <linux/err.h>
#include <linux/clocksource.h>
@ -110,12 +109,10 @@ static int sh_tmu_enable(struct sh_tmu_priv *p)
{
int ret;
/* wake up device and enable clock */
pm_runtime_get_sync(&p->pdev->dev);
/* enable clock */
ret = clk_enable(p->clk);
if (ret) {
dev_err(&p->pdev->dev, "cannot enable clock\n");
pm_runtime_put_sync(&p->pdev->dev);
return ret;
}
@ -144,9 +141,8 @@ static void sh_tmu_disable(struct sh_tmu_priv *p)
/* disable interrupts in TMU block */
sh_tmu_write(p, TCR, 0x0000);
/* stop clock and mark device as idle */
/* stop clock */
clk_disable(p->clk);
pm_runtime_put_sync(&p->pdev->dev);
}
static void sh_tmu_set_next(struct sh_tmu_priv *p, unsigned long delta,
@ -415,7 +411,6 @@ static int __devinit sh_tmu_probe(struct platform_device *pdev)
if (p) {
dev_info(&pdev->dev, "kept as earlytimer\n");
pm_runtime_enable(&pdev->dev);
return 0;
}
@ -430,9 +425,6 @@ static int __devinit sh_tmu_probe(struct platform_device *pdev)
kfree(p);
platform_set_drvdata(pdev, NULL);
}
if (!is_early_platform_device(pdev))
pm_runtime_enable(&pdev->dev);
return ret;
}