linux-kernel - Re: [PATCH 09/25] media: hantro: do a PM resume earlier

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Date:   Wed, 05 May 2021 11:01:35 -0300
From:   Ezequiel Garcia <ezequiel@...labora.com>
To:     Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
Cc:     linuxarm@...wei.com, mauro.chehab@...wei.com,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
        linux-rockchip@...ts.infradead.org, linux-staging@...ts.linux.dev
Subject: Re: [PATCH 09/25] media: hantro: do a PM resume earlier

On Wed, 2021-05-05 at 15:46 +0200, Mauro Carvalho Chehab wrote:
> Em Wed, 05 May 2021 10:22:03 -0300
> Ezequiel Garcia <ezequiel@...labora.com> escreveu:
> 
> > Hi Mauro,
> > 
> > Thanks for working on this.
> > 
> > On Wed, 2021-05-05 at 11:41 +0200, Mauro Carvalho Chehab wrote:
> > > The device_run() first enables the clock and then
> > > tries to resume PM runtime, checking for errors.
> > > 
> > > Well, if for some reason the pm_runtime can not resume,
> > > it would be better to detect it beforehand.
> > > 
> > > So, change the order inside device_run().
> > > 
> > > Reviewed-by: Ezequiel Garcia <ezequiel@...labora.com>
> > > Fixes: 775fec69008d ("media: add Rockchip VPU JPEG encoder driver")
> > > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>  
> > 
> > It seems this is wrong now, as this series doesn't have
> > 
> > https://lore.kernel.org/linux-media/803c39fafdd62efc6f9e4d99a372af2c6955143b.1619621413.git.mchehab+huawei@kernel.org/
> > 
> > I don't fully understand why all the back and forth
> > happening on this series, but the former Hantro patches
> > looked good (despite perhaps unclear commit messages).
> 
> There was a request to break the original /79 series into smaller ones,
> to make easier for reviewers. So, I opted to split it into (probably)
> 3 series:
> 
> 1. Fixes (this series);
> 2. "use pm_runtime_resume_and_get" for the I2C drivers;
> 3. "use pm_runtime_resume_and_get" for remaining ones.
> 
> Before flooding everybody's email's with series (2) and (3), better
> to focus at the fixes first. I'll probably send the other two series
> by tomorrow.
> 
> > Any issues just squashing these two commits from "[PATCH v4 00/79] Address some issues with PM runtime at media subsystem":
> > 
> >   media: hantro: use pm_runtime_resume_and_get()
> >   media: hantro: do a PM resume earlier
> 
> The problem is that pm_runtime_resume_and_get() was added only
> recently (Kernel v5.10). 
> 
> So, I opted to place the fix patches before the changes, as this
> way, most (all?) patches can be easily be backported to legacy Kernels
> as needed.
> 

Got it.

Maybe the better fix would be the squash of [PATCH v4 78/79] media: hantro: use pm_runtime_resume_and_get()
and [PATCH v4 79/79] media: hantro: do a PM resume earlier but keeping pm_runtime_get_sync.

And then you can replace the pm_runtime_get_sync with pm_runtime_resume_and_get.

Thanks,
Ezequiel