linux-kernel - Re: [PATCH v2 07/22] drm/msm: Do rpm get sooner in the submit path

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Date:   Mon, 7 Dec 2020 11:46:54 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Rob Clark <robdclark@...il.com>
Cc:     Daniel Vetter <daniel@...ll.ch>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Rob Clark <robdclark@...omium.org>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...ux.ie>,
        "open list:DRM DRIVER FOR MSM ADRENO GPU" 
        <linux-arm-msm@...r.kernel.org>,
        "open list:DRM DRIVER FOR MSM ADRENO GPU" 
        <freedreno@...ts.freedesktop.org>,
        open list <linux-kernel@...r.kernel.org>,
        "Menon, Nishanth" <nm@...com>
Subject: Re: [PATCH v2 07/22] drm/msm: Do rpm get sooner in the submit path

On 19-11-20, 11:35, Viresh Kumar wrote:
> On 18-11-20, 08:53, Rob Clark wrote:
> > On Tue, Nov 17, 2020 at 9:28 PM Viresh Kumar <viresh.kumar@...aro.org> wrote:
> > >
> > > On 17-11-20, 09:02, Rob Clark wrote:
> > > > With that on top of the previous patch,
> > >
> > > Don't you still have this ? Which fixed the lockdep in the remove path.
> > >
> > > https://lore.kernel.org/lkml/20201022080644.2ck4okrxygmkuatn@vireshk-i7/
> > >
> > > To make it clear you need these patches to fix the OPP stuff:
> > >
> > > //From 5.10-rc3 (the one from the above link).
> > > commit e0df59de670b ("opp: Reduce the size of critical section in _opp_table_kref_release()")
> 
> This fixes debugfs stuff while the OPP table is removed.
> 
> > > //Below two from linux-next
> > > commit ef43f01ac069 ("opp: Always add entries in dev_list with opp_table->lock held")
> > > commit 27c09484dd3d ("opp: Allocate the OPP table outside of opp_table_lock")
> 
> This fixes debugfs stuff while the OPP table is added.
> 
> > > This matches the diff I gave you earlier.
> > >
> > 
> > no, I did not have all three, only "opp: Allocate the OPP table
> > outside of opp_table_lock" plus the fixup.  But with all three:
> 
> And looking at the lockdep you gave now, it looks like we have a
> problem with OPP table's internal lock (opp_table->lock) as well apart
> from the global opp_table_lock.
> 
> I wish there was a way for me to reproduce the lockdep :(
> 
> I know this is exhausting for both of us and I really want to be over
> with it as soon as possible, this really should be the last patch
> here, please try this along with other two. This fixes the debugfs
> thing while the OPPs in the OPP table are removed (they are already
> added without a lock around debugfs stuff).
> 
> AFAIU, there is no further debugfs stuff that happens from within the
> locks and so this really should be the last patch unless I missed
> something.

Rob, were you able to test this patch ?

-- 
viresh