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From: Rajendra Nayak <rnayak@codeaurora.org>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Rob Clark <robdclark@gmail.com>, Sean Paul <sean@poorly.run>,
	linux-pm@vger.kernel.org,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Rafael Wysocki <rjw@rjwysocki.net>,
	Stephen Boyd <sboyd@kernel.org>, Nishanth Menon <nm@ti.com>,
	Douglas Anderson <dianders@chromium.org>,
	Naresh Kamboju <naresh.kamboju@linaro.org>,
	linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org,
	freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	saiprakash.ranjan@codeaurora.org
Subject: Re: [PATCH V2 3/8] drm/msm: Unconditionally call dev_pm_opp_of_remove_table()
Date: Tue, 1 Sep 2020 15:15:33 +0530	[thread overview]
Message-ID: <fceb0b09-30cd-5084-0d0e-e7795cfc5fc9@codeaurora.org> (raw)
In-Reply-To: <20200901083806.a2wz7idmfce2aj3a@vireshk-i7>


On 9/1/2020 2:08 PM, Viresh Kumar wrote:
> On 01-09-20, 13:01, Rajendra Nayak wrote:
>> So FWIU, dpu_unbind() gets called even when dpu_bind() fails for some reason.
> 
> Ahh, I see.
> 
>> 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.

> 
>> 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()?

[1] https://lore.kernel.org/patchwork/patch/1275628/
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  reply	other threads:[~2020-09-01  9:45 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-28  6:07 [PATCH V2 0/8] opp: Unconditionally call dev_pm_opp_of_remove_table() Viresh Kumar
2020-08-28  6:07 ` [PATCH V2 1/8] cpufreq: imx6q: " Viresh Kumar
2020-08-28  6:07 ` [PATCH V2 2/8] drm/lima: " Viresh Kumar
2020-10-22  5:14   ` Viresh Kumar
2020-08-28  6:07 ` [PATCH V2 3/8] drm/msm: " Viresh Kumar
2020-09-01  7:31   ` Rajendra Nayak
2020-09-01  8:38     ` Viresh Kumar
2020-09-01  9:45       ` Rajendra Nayak [this message]
2020-09-01  9:50         ` Viresh Kumar
2020-10-05  6:26   ` Viresh Kumar
2020-10-21  7:24     ` Viresh Kumar
2020-10-21 16:58       ` Rob Clark
2020-10-22  5:12         ` Viresh Kumar
2020-08-28  6:07 ` [PATCH V2 4/8] mmc: sdhci-msm: " Viresh Kumar
2020-08-28  8:43   ` Ulf Hansson
2020-08-28 15:06     ` Doug Anderson
2020-08-31  6:23     ` Viresh Kumar
2020-08-31 10:44     ` Viresh Kumar
2020-08-31 10:57       ` Ulf Hansson
2020-09-09 11:07         ` Viresh Kumar
2020-09-09 12:48           ` Ulf Hansson
2020-08-28  6:07 ` [PATCH V2 5/8] spi: spi-geni-qcom: " Viresh Kumar
2020-08-28  6:07 ` [PATCH V2 6/8] spi: spi-qcom-qspi: " Viresh Kumar
2020-08-28  6:07 ` [PATCH V2 7/8] tty: serial: qcom_geni_serial: " Viresh Kumar
2020-08-28  6:07 ` [PATCH V2 8/8] qcom-geni-se: remove has_opp_table Viresh Kumar
2020-10-21  7:34   ` Viresh Kumar
2020-10-21 15:31     ` Doug Anderson
2020-08-31 11:09 ` [PATCH V2 0/8] opp: Unconditionally call dev_pm_opp_of_remove_table() Viresh Kumar
2020-09-09 11:08   ` Viresh Kumar
2020-09-09 15:28 ` Mark Brown

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