linux-kernel - RE: [PATCH v2 4/7] media: chips-media: wave5: Use spinlock whenever statue is changed

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Message-ID:
 <SE1P216MB130368B2DDB6A235D2603E04ED64A@SE1P216MB1303.KORP216.PROD.OUTLOOK.COM>
Date: Tue, 27 May 2025 05:02:46 +0000
From: jackson.lee <jackson.lee@...psnmedia.com>
To: Nicolas Dufresne <nicolas.dufresne@...labora.com>, "mchehab@...nel.org"
	<mchehab@...nel.org>, "hverkuil-cisco@...all.nl" <hverkuil-cisco@...all.nl>,
	"bob.beckett@...labora.com" <bob.beckett@...labora.com>
CC: "linux-media@...r.kernel.org" <linux-media@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, lafley.kim
	<lafley.kim@...psnmedia.com>, "b-brnich@...com" <b-brnich@...com>,
	"hverkuil@...all.nl" <hverkuil@...all.nl>, Nas Chung
	<nas.chung@...psnmedia.com>
Subject: RE: [PATCH v2 4/7] media: chips-media: wave5: Use spinlock whenever
 statue is changed

Hi Nicolas

> -----Original Message-----
> From: Nicolas Dufresne <nicolas.dufresne@...labora.com>
> Sent: Saturday, May 24, 2025 2:41 AM
> To: jackson.lee <jackson.lee@...psnmedia.com>; mchehab@...nel.org;
> hverkuil-cisco@...all.nl; sebastian.fricke@...labora.com;
> bob.beckett@...labora.com; dafna.hirschfeld@...labora.com
> Cc: linux-media@...r.kernel.org; linux-kernel@...r.kernel.org; lafley.kim
> <lafley.kim@...psnmedia.com>; b-brnich@...com; hverkuil@...all.nl; Nas
> Chung <nas.chung@...psnmedia.com>
> Subject: Re: [PATCH v2 4/7] media: chips-media: wave5: Use spinlock
> whenever statue is changed
> 
> Hi,
> 
> Le jeudi 22 mai 2025 à 16:26 +0900, Jackson.lee a écrit :
> > From: Jackson Lee <jackson.lee@...psnmedia.com>
> >
> > The device_run and finish_decode is not any more synchronized, so lock
> > was needed in the device_run whenever state was changed.
> 
> Can you try to introduce the locking ahead of the patches, otherwise this
> break bisectability as the in-between become racy.


Do you want to introduce this patch ahead of the performance patch?

Thanks
Jackson

> 
> Nicolas
> 
> >
> > Signed-off-by: Jackson Lee <jackson.lee@...psnmedia.com>
> > Signed-off-by: Nas Chung <nas.chung@...psnmedia.com>
> > ---
> >  drivers/media/platform/chips-media/wave5/wave5-vpu-dec.c | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/platform/chips-media/wave5/wave5-vpu-dec.c
> > b/drivers/media/platform/chips- media/wave5/wave5-vpu-dec.c index
> > 42981c3b49bc..719c5527eb7f 100644
> > --- a/drivers/media/platform/chips-media/wave5/wave5-vpu-dec.c
> > +++ b/drivers/media/platform/chips-media/wave5/wave5-vpu-dec.c
> > @@ -1577,6 +1577,7 @@ static void wave5_vpu_dec_device_run(void *priv)
> >  	struct queue_status_info q_status;
> >  	u32 fail_res = 0;
> >  	int ret = 0;
> > +	unsigned long flags;
> >
> >  	dev_dbg(inst->dev->dev, "%s: Fill the ring buffer with new
> bitstream data", __func__);
> >  	pm_runtime_resume_and_get(inst->dev->dev);
> > @@ -1617,7 +1618,9 @@ static void wave5_vpu_dec_device_run(void *priv)
> >  			}
> >  			spin_unlock_irqrestore(&inst->state_spinlock, flags);
> >  		} else {
> > +			spin_lock_irqsave(&inst->state_spinlock, flags);
> >  			switch_state(inst, VPU_INST_STATE_INIT_SEQ);
> > +			spin_unlock_irqrestore(&inst->state_spinlock, flags);
> >  		}
> >
> >  		break;
> > @@ -1628,8 +1631,9 @@ static void wave5_vpu_dec_device_run(void *priv)
> >  		 * we had a chance to switch, which leads to an invalid state
> >  		 * change.
> >  		 */
> > +		spin_lock_irqsave(&inst->state_spinlock, flags);
> >  		switch_state(inst, VPU_INST_STATE_PIC_RUN);
> > -
> > +		spin_unlock_irqrestore(&inst->state_spinlock, flags);
> >  		/*
> >  		 * During DRC, the picture decoding remains pending, so just
> leave the job
> >  		 * active until this decode operation completes.
> > @@ -1643,7 +1647,9 @@ static void wave5_vpu_dec_device_run(void *priv)
> >  		ret = wave5_prepare_fb(inst);
> >  		if (ret) {
> >  			dev_warn(inst->dev->dev, "Framebuffer preparation,
> fail: %d\n",
> > ret);
> > +			spin_lock_irqsave(&inst->state_spinlock, flags);
> >  			switch_state(inst, VPU_INST_STATE_STOP);
> > +			spin_unlock_irqrestore(&inst->state_spinlock, flags);
> >  			break;
> >  		}
> >