Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Thomas Gleixner <tglx@linutronix.de>
To:     Saravana Kannan <saravanak@google.com>,
        Ionela Voinescu <ionela.voinescu@arm.com>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        linux-tip-commits@vger.kernel.org, x86 <x86@kernel.org>,
        liviu.dudau@arm.com, sudeep.holla@arm.com,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Jon Hunter <jonathanh@nvidia.com>
Subject: Re: [tip: timers/core] clocksource/drivers/timer-probe: Avoid creating dead devices
In-Reply-To: <CAGETcx80wvGnS0-MwJ9M9RR9Mny0jmmep+JfwaUJUOR2bfJYsQ@mail.gmail.com>
References: <20200111052125.238212-1-saravanak@google.com> <158460766637.28353.11325960928759668587.tip-bot2@tip-bot2> <20200324175955.GA16972@arm.com> <CAGETcx8Qhy3y66vJyi8kRvg1+hXf-goDvyty-bsG5qFrA-CKgg@mail.gmail.com> <CAGETcx80wvGnS0-MwJ9M9RR9Mny0jmmep+JfwaUJUOR2bfJYsQ@mail.gmail.com>
Date:   Wed, 25 Mar 2020 22:47:25 +0100
Message-ID: <87lfnoxg2a.fsf@nanos.tec.linutronix.de>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Saravana Kannan <saravanak@google.com> writes:
> On Tue, Mar 24, 2020 at 11:34 AM Saravana Kannan <saravanak@google.com> wrote:
> I took a closer look. So two different drivers [1] [2] are saying they
> know how to handle "arm,vexpress-sysreg" and are expecting to run at
> the same time. That seems a bit unusual to me. I wonder if this is a
> violation of the device-driver model because this expectation would
> never be allowed if these device drivers were actual drivers
> registered with driver-core. But that's a discussion for another time.
>
> To fix this issue you are facing, this patch should work:
> https://lore.kernel.org/lkml/20200324195302.203115-1-saravanak@google.com/T/#u

Sorry, that's not a fix. That's a crude hack.

As this is also causing trouble on tegra30-cardhu-a04 the only sane
solution is to revert it and start over with a proper solution for the
vexpress problem and a root cause analysis for the tegra.

Thanks,

        tglx