[PATCH 4/6] usb: musb: Add missing pm_runtime_disable and drop 2430 PM timeout

[Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>]

We are missing pm_runtime_disable() in 2430 glue layer. Further,
we only need to enable PM runtime and disable it on exit. With
musb_core.c doing PM, the glue layer as a parent will always be
active when musb_core.c is active.

This fixes host enumeration issues with some devices as reported
by Ladislav Michl <ladis-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org>.

And holding an RPM reference while deregistering the child would
lead to a crash in omap2430_runtime_suspend() which dereferences
the now freed child's driver data on put as pointed out by
Johan Hovold <johan-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>:

Unable to handle kernel paging request at virtual address 6b6b6f17
...
[<c05453d4>] (omap2430_runtime_suspend) from [<c0481410>]
 (pm_generic_runtime_suspend+0x3c/0x48)
[<c0481410>] (pm_generic_runtime_suspend) from [<c0121028>]
 (_od_runtime_suspend+0x1c/0x30)
[<c0121028>] (_od_runtime_suspend) from [<c04833b0>] (__rpm_callback+0x3c/0x70)
[<c04833b0>] (__rpm_callback) from [<c0483414>] (rpm_callback+0x30/0x90)
[<c0483414>] (rpm_callback) from [<c0483984>] (rpm_suspend+0x118/0x6b4)
[<c0483984>] (rpm_suspend) from [<c04840f4>] (rpm_idle+0x104/0x440)
[<c04840f4>] (rpm_idle) from [<c04844ac>] (__pm_runtime_idle+0x7c/0xb0)
[<c04844ac>] (__pm_runtime_idle) from [<c0545458>] (omap2430_remove+0x38/0x58)
[<c0545458>] (omap2430_remove) from [<c047b2bc>] (platform_drv_remove+0x34/0x4c)

Note that if changes are needed to the autosuspend timeout, it should
be done in musb_core.c.

Reported-by: Ladislav Michl <ladis-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org>
Fixes: 87326e858448 ("usb: musb: Remove extra PM runtime calls from
2430 glue layer")
Tested-by: Ladislav Michl <ladis-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org>
Reviewed-by: Johan Hovold <johan-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Tested-by: Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
Signed-off-by: Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>
---
 drivers/usb/musb/omap2430.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/musb/omap2430.c b/drivers/usb/musb/omap2430.c
--- a/drivers/usb/musb/omap2430.c
+++ b/drivers/usb/musb/omap2430.c
@@ -513,17 +513,18 @@ static int omap2430_probe(struct platform_device *pdev)
 	}
 
 	pm_runtime_enable(glue->dev);
-	pm_runtime_use_autosuspend(glue->dev);
-	pm_runtime_set_autosuspend_delay(glue->dev, 100);
 
 	ret = platform_device_add(musb);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to register musb device\n");
-		goto err2;
+		goto err3;
 	}
 
 	return 0;
 
+err3:
+	pm_runtime_disable(glue->dev);
+
 err2:
 	platform_device_put(musb);
 
@@ -535,10 +536,7 @@ static int omap2430_remove(struct platform_device *pdev)
 {
 	struct omap2430_glue *glue = platform_get_drvdata(pdev);
 
-	pm_runtime_get_sync(glue->dev);
 	platform_device_unregister(glue->musb);
-	pm_runtime_put_sync(glue->dev);
-	pm_runtime_dont_use_autosuspend(glue->dev);
 	pm_runtime_disable(glue->dev);
 
 	return 0;
-- 
2.10.2
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