On 01-09-20, 15:15, Rajendra Nayak wrote:

On 9/1/2020 2:08 PM, Viresh Kumar wrote:

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On 01-09-20, 13:01, Rajendra Nayak wrote:

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So FWIU, dpu_unbind() gets called even when dpu_bind() fails for some reason.

Ahh, I see.

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I tried to address that earlier [1] which I realized did not land.

I don't think that patch was required, as you can call
dev_pm_opp_put_clkname() multiple times and it will return without any
errors/crash.

We did see a crash (Sai had reported it), perhaps with dsi [1] and not this
driver. But it was the same scenario that was possible here as well, which is
dev_pm_opp_put_clkname() getting called without dev_pm_opp_set_clkname()
being done. I think we ended up passing a NULL as opp_table in that case
and the function tries de-referencing it.

Heh, yeah I did miss that stupid thing :(

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But with these changes
it will be even more broken unless we identify if we failed dpu_bind() before
adding the OPP table, while adding it, or all went well with opps and handle things
accordingly in dpu_unbind.

Maybe not as dev_pm_opp_of_remove_table() can be called multiple times
as well without any errors or crash.

Can it be called without the driver ever doing a dev_pm_opp_of_add_table()?

Yes, as we will fail to find the OPP device in that case with -ENODEV
and so won't even print a warning.

Also if the OPP table was previously added as a response to
dev_pm_opp_set_clkname(), then we won't free it as well. So yes, it
should work just fine.

-- 
viresh