Re: [PATCH 3/8] drm/ingenic: Use standard drm_atomic_helper_commit_tail

[Paul Cercueil]

Hi Daniel,

Le mar., août 10 2021 at 12:20:38 +0200, Daniel Vetter 
<daniel@xxxxxxxx> a écrit :
> On Sun, Aug 08, 2021 at 03:45:21PM +0200, Paul Cercueil wrote:
> >  By making the CRTC's .vblank_enable() function return an error when 
> > it
> >  is known that the hardware won't deliver a VBLANK, we can drop the
> >  ingenic_drm_atomic_helper_commit_tail() function and use the 
> > standard
> >  drm_atomic_helper_commit_tail() function instead.
> >
> >  Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
> >  ---
> >   drivers/gpu/drm/ingenic/ingenic-drm-drv.c | 28 
> > ++++-------------------
> >   1 file changed, 4 insertions(+), 24 deletions(-)
> >
> >  diff --git a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c 
> > b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> >  index bc71ba44ccf4..3ed7c27a8dde 100644
> >  --- a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> >  +++ b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> >  @@ -706,29 +706,6 @@ static int 
> > ingenic_drm_encoder_atomic_check(struct drm_encoder *encoder,
> >   	}
> >   }
> >
> >  -static void ingenic_drm_atomic_helper_commit_tail(struct 
> > drm_atomic_state *old_state)
> >  -{
> >  -	/*
> >  -	 * Just your regular drm_atomic_helper_commit_tail(), but only 
> > calls
> >  -	 * drm_atomic_helper_wait_for_vblanks() if priv->no_vblank.
> >  -	 */
> >  -	struct drm_device *dev = old_state->dev;
> >  -	struct ingenic_drm *priv = drm_device_get_priv(dev);
> >  -
> >  -	drm_atomic_helper_commit_modeset_disables(dev, old_state);
> >  -
> >  -	drm_atomic_helper_commit_planes(dev, old_state, 0);
> >  -
> >  -	drm_atomic_helper_commit_modeset_enables(dev, old_state);
> >  -
> >  -	drm_atomic_helper_commit_hw_done(old_state);
> >  -
> >  -	if (!priv->no_vblank)
> >  -		drm_atomic_helper_wait_for_vblanks(dev, old_state);
> >  -
> >  -	drm_atomic_helper_cleanup_planes(dev, old_state);
> >  -}
> >  -
> >   static irqreturn_t ingenic_drm_irq_handler(int irq, void *arg)
> >   {
> >   	struct ingenic_drm *priv = drm_device_get_priv(arg);
> >  @@ -749,6 +726,9 @@ static int ingenic_drm_enable_vblank(struct 
> > drm_crtc *crtc)
> >   {
> >   	struct ingenic_drm *priv = drm_crtc_get_priv(crtc);
> >
> >  +	if (priv->no_vblank)
> >  +		return -EWOULDBLOCK;
>
> I think other drivers return EINVAL here. I'm not sure exactly this is
> specified, but the errno here is visible to userspace.
>
> Maybe would be good to update the kerneldoc for this hook?
>
> Anyway this is great, with the errno fixed:
>
> Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>

I thought about it afterwards, that my error code wasn't great. In my 
mind it was "the driver will hang while waiting for vblank" hence 
-EWOULDBLOCK ;)

I'll need to v2 anyway so I'll change it to -EINVAL then.

Cheers,
-Paul

> >  +
> >   	regmap_update_bits(priv->map, JZ_REG_LCD_CTRL,
> >   			   JZ_LCD_CTRL_EOF_IRQ, JZ_LCD_CTRL_EOF_IRQ);
> >
> >  @@ -856,7 +836,7 @@ static const struct drm_mode_config_funcs 
> > ingenic_drm_mode_config_funcs = {
> >   };
> >
> >   static struct drm_mode_config_helper_funcs 
> > ingenic_drm_mode_config_helpers = {
> >  -	.atomic_commit_tail = ingenic_drm_atomic_helper_commit_tail,
> >  +	.atomic_commit_tail = drm_atomic_helper_commit_tail,
> >   };
> >
> >   static void ingenic_drm_unbind_all(void *d)
> >  --
> >  2.30.2
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch