On 07/08/18 13:09, Heiko Stuebner wrote:

Hi Marc,

Am Dienstag, 7. August 2018, 10:54:05 CEST schrieb Marc Zyngier:

quoted

pm_runtime_get_if_in_use can fail: either PM has been disabled
altogether (-EINVAL), or the device hasn't been enabled yet (0).
Sadly, the Rockchip IOMMU driver tends to conflate the two things
by considering a non-zero return value as successful.

This has the consequence of hiding other bugs, so let's handle this
case throughout the driver, with a WARN_ON_ONCE so that we can try
and work out what happened.

Fixes: 0f181d3cf7d98 ("iommu/rockchip: Add runtime PM support")
Signed-off-by: Marc Zyngier <redacted>

I'm still not sure about the !CONFIG_PM case, as it was probably silently
working in that case before

Do we agree that this is an orthogonal problem though?

But on the other hand we're also already running over it in other places
like in the iommu-shutdown and I guess if someone _really_ disabled
CONFIG_PM, a lot of additional stuff would fail anyway.

So should we wrap that in some #ifdef magic, just ignore it or simply
select PM similar to what Tegra, Renesas and Vexpress seem to do?

I guess I like the 3rd option best ;-)

It probably doesn't hurt. At what level do you want it? As a dependency
to the IOMMU? or to the platform?

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...