On Fri, Nov 11, 2016 at 10:43:01AM -0800, Tony Lindgren wrote:
> 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.
In fact, we have to do this way to avoid a crash in omap2430_remove().
> This fixes host enumeration issues with some devices as reported
> by Ladislav Michl <la...@linux-mips.org>.
>
> If changes are needed to the autosuspend timeout, it should be
> done in musb_core.c.
>
> Reported-by: Ladislav Michl <la...@linux-mips.org>
> Fixes: 87326e858448 ("usb: musb: Remove extra PM runtime calls from
> 2430 glue layer")
> Tested-by: Ladislav Michl <la...@linux-mips.org>
> Signed-off-by: Tony Lindgren <t...@atomide.com>
> @@ -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);
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.
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)
> - pm_runtime_dont_use_autosuspend(glue->dev);
> pm_runtime_disable(glue->dev);
>
> return 0;
This might be worth mentioning in the commit message, but feel free to
add
Reviewed-by: Johan Hovold <jo...@kernel.org>
either way.
Thanks,
Johan
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