Re: [PATCH] drm: shmob_drm: Check clk_prepare_enable() return value

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

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Hello,

On Wednesday 04 December 2013 16:59:22 Thierry Reding wrote:
> On Wed, Dec 04, 2013 at 03:37:48PM +0100, Laurent Pinchart wrote:
> > On Wednesday 04 December 2013 11:01:07 Thierry Reding wrote:
> > > On Wed, Dec 04, 2013 at 02:38:21AM +0100, Laurent Pinchart wrote:
> > > > On Tuesday 03 December 2013 10:59:24 Thierry Reding wrote:
> > > > > On Mon, Dec 02, 2013 at 01:52:20AM +0100, Laurent Pinchart wrote:
> > > > > [...]
> > > > > 
> > > > > > diff --git a/drivers/gpu/drm/shmobile/shmob_drm_crtc.c
> > > > > > b/drivers/gpu/drm/shmobile/shmob_drm_crtc.c
> > > > > 
> > > > > [...]
> > > > > 
> > > > > > @@ -170,7 +178,9 @@ static void shmob_drm_crtc_start(struct
> > > > > > shmob_drm_crtc *scrtc)
> > > > > >  		return;
> > > > > >  	
> > > > > >  	/* Enable clocks before accessing the hardware. */
> > > > > > -	shmob_drm_clk_on(sdev);
> > > > > > +	ret = shmob_drm_clk_on(sdev);
> > > > > > +	if (ret < 0)
> > > > > > +		return;
> > > > > 
> > > > > Perhaps this should be printing an error or using WARN_ON()?
> > > > > Otherwise it might be very difficult to diagnose what's going wrong.
> > > > 
> > > > That's a good point. In practice, as the driver always uses a Renesas
> > > > SoC MSTP clock, the clock code will print a message to the kernel log
> > > > though, so I'm not sure whether we should duplicate that here. If you
> > > > think we should I'll submit a new patch.
> > > 
> > > Is that one of the clocks implemented in drivers/sh/clk?
> > 
> > Correct, and in drivers/clk/shmobile/clk-mstp.c when
> > http://www.spinics.net/lists/devicetree/msg12696.html will be merged.
> > 
> > > There don't seem to be any error messages in the clk_enable()
> > > implementation.
> > 
> > There will be one when http://www.spinics.net/lists/linux-sh/msg25650.html
> > will get merged :-) Before that enabling the clock never failed, with the
> > patch applied the failure is logged.
> 
> Alright,
> 
> Reviewed-by: Thierry Reding <treding@nvidia.com>

Thank you.

Dave, could you please pick this patch up for v3.14 ?

-- 
Regards,

Laurent Pinchart

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