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SubjectRe: [Regression, post-3.5] System suspend broken on the Mackerel board
On Sat, Jul 28, 2012 at 12:53:11AM +0200, Rafael J. Wysocki wrote:
> Unfortunately, your commit
>
> commit ca5481c68e9fbcea62bb3c78ae6cccf99ca8fb73
> Author: Paul Mundt <lethal@linux-sh.org>
> Date: Tue Jul 10 12:08:14 2012 +0900
>
> sh: pfc: Rudimentary pinctrl-backed GPIO support.
>
> breaks system suspend on the Mackerel board (.config attached). The system
> simply doesn't suspend and instead it hangs somewhere while suspending
> devices (apparently before running the "late" callbacks).
>
> If the above commit is reverted, system suspend works normally.

On Tue, Jul 31, 2012 at 08:57:02PM -0700, kuninori.morimoto.gx@renesas.com wrote:
> gpio: sh7724_pfc handling gpio 0 -> 486
> core: sh7724_pfc support registered
> HW Breakpoints: SH-4A UBC support registered
> autorequest GPIO-53
> ------------[ cut here ]------------
> WARNING: at /opt/usr/src/WORK/morimoto/gitlinux/linux-2.6/drivers/gpio/gpiolib.3
> Modules linked in:
>
> Pid : 1, Comm: swapper
> CPU : 0 Not tainted (3.5.0-rc6+ #1407)
>
> PC is at gpio_ensure_requested+0x30/0x78
> PR is at gpio_ensure_requested+0x30/0x78

Morimoto-san's logs off-list made it clear what happened. Both of these
platforms are going gpio_request() calls at arch_initcall() time which
completely screwed up the ordering of the pfc core. We seem to -ENODEV
out in one place due to missing a pfc pointer initialization elsewhere
resulting in -EPROBE_DEFER from gpiolib.

Turns out we can just collapse the probe/init stuff anyways, so this
ought to fix it. I've verified that it fixes Morimoto-san's issue, my
expectation is that the mackerel case is likewise getting tripped up but
no one bothered implementing any error detecting logic for gpio_request()
failing, so it doesn't fail gracefully.

I'll be pushing this out to Linus shortly:

---

commit 1e32dfe323d156d5d7b25b9feffe015d19713db2
Author: Paul Mundt <lethal@linux-sh.org>
Date: Wed Aug 1 16:27:38 2012 +0900

sh: pfc: Fix up init ordering mess.

Commit ca5481c68e9fbcea62bb3c78ae6cccf99ca8fb73 ("sh: pfc: Rudimentary
pinctrl-backed GPIO support.") introduced a regression for platforms that
were doing early GPIO API calls (from arch_initcall() or earlier),
leading to a situation where our two-stage registration logic would trip
itself up and we'd -ENODEV out of the pinctrl registration path,
resulting in endless -EPROBE_DEFER errors. Further lack of checking any
sort of errors from gpio_request() resulted in boot time warnings,
tripping on the FLAG_REQUESTED test-and-set in gpio_ensure_requested().

As it turns out there's no particular need to bother with the two-stage
registration, as the platform bus is already available at the point that
we have to start caring. As such, it's easiest to simply fold these
together in to a single init path, the ordering of which is ensured
through the platform's mux registration, as usual.

Reported-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

diff --git a/drivers/sh/pfc/pinctrl.c b/drivers/sh/pfc/pinctrl.c
index 814b292..2804eaa 100644
--- a/drivers/sh/pfc/pinctrl.c
+++ b/drivers/sh/pfc/pinctrl.c
@@ -325,20 +325,6 @@ static struct pinctrl_desc sh_pfc_pinctrl_desc = {
.confops = &sh_pfc_pinconf_ops,
};

-int sh_pfc_register_pinctrl(struct sh_pfc *pfc)
-{
- sh_pfc_pmx = kzalloc(sizeof(struct sh_pfc_pinctrl), GFP_KERNEL);
- if (unlikely(!sh_pfc_pmx))
- return -ENOMEM;
-
- spin_lock_init(&sh_pfc_pmx->lock);
-
- sh_pfc_pmx->pfc = pfc;
-
- return 0;
-}
-EXPORT_SYMBOL_GPL(sh_pfc_register_pinctrl);
-
static inline void __devinit sh_pfc_map_one_gpio(struct sh_pfc *pfc,
struct sh_pfc_pinctrl *pmx,
struct pinmux_gpio *gpio,
@@ -505,7 +491,7 @@ static struct platform_device sh_pfc_pinctrl_device = {
.id = -1,
};

-static int __init sh_pfc_pinctrl_init(void)
+static int sh_pfc_pinctrl_init(void)
{
int rc;

@@ -519,10 +505,22 @@ static int __init sh_pfc_pinctrl_init(void)
return rc;
}

+int sh_pfc_register_pinctrl(struct sh_pfc *pfc)
+{
+ sh_pfc_pmx = kzalloc(sizeof(struct sh_pfc_pinctrl), GFP_KERNEL);
+ if (unlikely(!sh_pfc_pmx))
+ return -ENOMEM;
+
+ spin_lock_init(&sh_pfc_pmx->lock);
+
+ sh_pfc_pmx->pfc = pfc;
+
+ return sh_pfc_pinctrl_init();
+}
+EXPORT_SYMBOL_GPL(sh_pfc_register_pinctrl);
+
static void __exit sh_pfc_pinctrl_exit(void)
{
platform_driver_unregister(&sh_pfc_pinctrl_driver);
}
-
-subsys_initcall(sh_pfc_pinctrl_init);
module_exit(sh_pfc_pinctrl_exit);

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