Re: [PATCH v1 0/3] Bring back driver_deferred_probe_check_state() for now

From: Doug Anderson <dianders@chromium.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Saravana Kannan <saravanak@google.com>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Kevin Hilman <khilman@kernel.org>,
	Ulf Hansson <ulf.hansson@linaro.org>, Pavel Machek <pavel@ucw.cz>,
	Len Brown <len.brown@intel.com>, Andrew Lunn <andrew@lunn.ch>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	Russell King <linux@armlinux.org.uk>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Naresh Kamboju <naresh.kamboju@linaro.org>,
	kernel-team@android.com, LKML <linux-kernel@vger.kernel.org>,
	Linux PM <linux-pm@vger.kernel.org>,
	netdev <netdev@vger.kernel.org>,
	Stephen Boyd <swboyd@chromium.org>
Subject: Re: [PATCH v1 0/3] Bring back driver_deferred_probe_check_state() for now
Date: Tue, 9 Aug 2022 16:46:46 -0700	[thread overview]
Message-ID: <CAD=FV=W1P=4vzyTYQ+yVC=fH-7i=hjCAk7FV8jcGcGY+xa62pA@mail.gmail.com> (raw)
In-Reply-To: <YuI6shUi6iJdMSfB@kroah.com>

Hi,

On Thu, Jul 28, 2022 at 12:29 AM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Wed, Jul 27, 2022 at 11:50:08AM -0700, Saravana Kannan wrote:
> > More fixes/changes are needed before driver_deferred_probe_check_state()
> > can be deleted. So, bring it back for now.
> >
> > Greg,
> >
> > Can we get this into 5.19? If not, it might not be worth picking up this
> > series. I could just do the other/more fixes in time for 5.20.
>
> Wow, no, it is _WAY_ too late for 5.19 to make a change like this,
> sorry.
>
> What is so broken that we need to revert these now?  I could do so for
> 5.20-rc1, and then backport to 5.19.y if that release is really broken,
> but this feels odd so late in the cycle.

I spent a bunch of time bisecting mainline today on my
sc7180-trogdor-lazor board. When building the top of Linus's tree
today the display doesn't come up. I can make it come up by turning
fw_devlink off (after fixing a regulator bug that I just posted a fix
for).

I found that the first bad commit was commit 5a46079a9645 ("PM:
domains: Delete usage of driver_deferred_probe_check_state()")

...but only when applied to mainline. When I cherry-pick that back to
v5.19-rc1 (and pick another bugfix needed to boot my board against
v5.19-rc1) then it works OK. After yet more bisecting, I found that on
trogdor there's a bad interaction with the commit e511a760 ("arm64:
dts: qcom: sm7180: remove assigned-clock-rate property for mdp clk").
That commit is perfectly legit but I guess it somehow changed how
fw_devlink was interpreting things?

Sure enough, picking this revert series fixes things on Linus's tree.
Any chance we can still get the revert in for v5.20-rc1? ;-)

-Doug