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Commit d4905ce3 authored by Paul Mundt's avatar Paul Mundt
Browse files

Revert "clocksource: sh_tmu: Runtime PM support" 



This reverts commit 1b842e91.

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: default avatarPaul Mundt <lethal@linux-sh.org>
parent db7eba29

drivers/clocksource/sh_tmu.c

+2 −10
Original line number Diff line number Diff line
@@ -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;

}