linux-kernel - Re: [PATCH v2 6/8] drm/arm/malidp: Enable/disable the scaling engine interrupts with memory writeback

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Message-ID: <20180424101156.GA17307@arm.com>
Date:   Tue, 24 Apr 2018 11:11:56 +0100
From:   Ayan Halder <ayan.halder@....com>
To:     Liviu Dudau <liviu.dudau@....com>
Cc:     brian.starkey@....com, malidp@...s.arm.com, airlied@...ux.ie,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        nd@....com
Subject: Re: [PATCH v2 6/8] drm/arm/malidp: Enable/disable the scaling engine
 interrupts with memory writeback

Hi Liviu,

On Mon, Apr 23, 2018 at 04:36:47PM +0100, Liviu Dudau wrote:
> On Mon, Apr 23, 2018 at 03:50:49PM +0100, Ayan Kumar Halder wrote:
> > Scaling engine interrupts need to be enabled/disabled as and when memwrite
> > is enabled and disabled. The reason being scaling engine interrupts are
> > used only by the memory writeout layer.
> > 
> > This patch depends on:
> > https://lkml.org/lkml/2017/5/15/695
> > 
> > Signed-off-by: Ayan Kumar Halder <ayan.halder@....com>
> > 
> > ---
> > Changes in v2:-
> > - Removed the change id and modified the commit message
> > ---
> >  drivers/gpu/drm/arm/malidp_hw.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/arm/malidp_hw.c b/drivers/gpu/drm/arm/malidp_hw.c
> > index f5633bc..90d76e4 100644
> > --- a/drivers/gpu/drm/arm/malidp_hw.c
> > +++ b/drivers/gpu/drm/arm/malidp_hw.c
> > @@ -621,12 +621,14 @@ static int malidp550_enable_memwrite(struct malidp_hw_device *hwdev,
> >  	malidp_hw_setbits(hwdev, MALIDP550_SE_MEMWRITE_ONESHOT | MALIDP_SE_MEMWRITE_EN,
> >  			  MALIDP550_SE_CONTROL);
> >  
> > +	malidp_se_irq_hw_init(hwdev);
> >  	return 0;
> >  }
> >  
> >  static void malidp550_disable_memwrite(struct malidp_hw_device *hwdev)
> >  {
> >  	u32 base = malidp_get_block_base(hwdev, MALIDP_DE_BLOCK);
> > +	malidp_se_irq_fini(hwdev);
> >  	malidp_hw_clearbits(hwdev, MALIDP550_SE_MEMWRITE_ONESHOT | MALIDP_SE_MEMWRITE_EN,
> >  			    MALIDP550_SE_CONTROL);
> >  	malidp_hw_clearbits(hwdev, MALIDP_SCALE_ENGINE_EN, base + MALIDP_DE_DISPLAY_FUNC);
> 
> We now know that this patch is broken, because it disables interrupts
> for the writeback after a previous commit has enabled them but before
> the writeback engine has finished writing, so the better place for
> enabling and disabling the SE IRQs is in the malidp_pm_{suspend,resume}
> functions, not here.
>
Sorry, I missed this issue. I will send an updated v3 patch for this
only.

Thanks,
Ayan Kumar Halder
> Only for this patch: NACK.
> 
> Best regards,
> Liviu
> 
> > -- 
> > 2.7.4
> > 
> 
> -- 
> ====================
> | I would like to |
> | fix the world,  |
> | but they're not |
> | giving me the   |
>  \ source code!  /
>   ---------------
>     ??\_(???)_/??