At Mon, 22 Jun 2015 11:30:34 +0100, Mark Brown wrote:
On Mon, Jun 22, 2015 at 11:58:24AM +0200, Takashi Iwai wrote:
In addition to rsnd-card.c, I get a compile warning as below:
sound/soc/mediatek/mtk-afe-pcm.c:1035:12: warning: 'mtk_afe_runtime_suspend' defined but not used [-Wunused-function]
And, looking at the code, it seems calling runtime suspend in the following way at probe:
pm_runtime_enable(&pdev->dev); if (!pm_runtime_enabled(&pdev->dev)) { ret = mtk_afe_runtime_resume(&pdev->dev); if (ret) goto err_pm_disable; }I'm confused, where's the call to runtime suspend?
It's in static const struct dev_pm_ops mtk_afe_pm_ops = { SET_RUNTIME_PM_OPS(mtk_afe_runtime_suspend, mtk_afe_runtime_resume, NULL) };
But my concern above isn't about the warning itself. I just stumbled on the code invoking runtime resume while looking at this warning, and wondered the behavior with CONFIG_PM=n.
Usually this kind of warning could be simply fixed by adding a proper ifdef. But, this driver calls runtime resume in the probe manually.
I'm not sure whether this really behaves correctly, especially when a kernel is built without CONFIG_PM.
Could you be more specific about the problem you're seeing? If runtime PM is disabled pm_runtime_enabled() will return false and we'll run through the resume path during probe() instead, otherwise we'll runtime resume whenever we need to use the hardware.
The runtime suspend is never called when CONFIG_PM=n. OTOH, we call runtime resume *always* at probe when CONFIG_PM=n. This looks inconsistent to me.
If it's a part of the mandatory initialization, it should be named explicitly so, and make the runtime resume callback just calls it instead.
Takashi