Re: [PATCH v3 6/6] drm: arc: Use crtc->mode_valid() callback

From: Daniel Vetter <daniel@ffwll.ch>
To: "Jose Abreu" <Jose.Abreu@synopsys.com>,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	"Carlos Palminha" <CARLOS.PALMINHA@synopsys.com>,
	"Alexey Brodkin" <Alexey.Brodkin@synopsys.com>,
	"Ville Syrjälä" <ville.syrjala@linux.intel.com>,
	"Dave Airlie" <airlied@linux.ie>,
	"Andrzej Hajda" <a.hajda@samsung.com>,
	"Archit Taneja" <architt@codeaurora.org>
Subject: Re: [PATCH v3 6/6] drm: arc: Use crtc->mode_valid() callback
Date: Mon, 15 May 2017 17:52:49 +0200	[thread overview]
Message-ID: <20170515155249.uzgqvy4ftpjlkclu@phenom.ffwll.local> (raw)
In-Reply-To: <20170515085325.aprm5qw2ril5eb5x@phenom.ffwll.local>

On Mon, May 15, 2017 at 10:53:25AM +0200, Daniel Vetter wrote:
> On Thu, May 11, 2017 at 10:06:02AM +0100, Jose Abreu wrote:
> > Now that we have a callback to check if crtc supports a given mode
> > we can use it in arcpgu so that we restrict the number of probbed
> > modes to the ones we can actually display.
> > 
> > This is specially useful because arcpgu crtc is responsible to set
> > a clock value in the commit() stage but unfortunatelly this clock
> > does not support all the needed ranges.
> > 
> > Also, remove the atomic_check() callback as mode_valid() callback
> > will be called before.
> > 
> > Signed-off-by: Jose Abreu <joabreu@synopsys.com>
> > Cc: Carlos Palminha <palminha@synopsys.com>
> > Cc: Alexey Brodkin <abrodkin@synopsys.com>
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> > Cc: Dave Airlie <airlied@linux.ie>
> > Cc: Andrzej Hajda <a.hajda@samsung.com>
> > Cc: Archit Taneja <architt@codeaurora.org>
> 
> Btw for justifying your patch series a bit more, would be real sweet to
> roll ->mode_valid out to more drivers. I see two easy cases:
> 
> bridge/analogix-anx78xx.c: has a simple mode_fixup which really is just a
> mode_valid callback
> 
> bridge/synopsys/dw-hdmi.c: simply hand-rolls what you've done here, we
> could move the connector_mode valid to the bridge and done.
> 
> Care to type these 2 patches on top, just to make this a bit more useful
> and a clearer case for merging?

Aside: There's a pile more drivers (encoders and crtc drivers) which would
similarly benefit and dont really look like they'd be hard to patch up:
- malidp_crtc_mode_fixup
- armada_drm_crtc_mode_fixup (armada isn't atomic, so forget this one)
- atmel_hlcdc_crtc_mode_fixup
- hdmi_mode_fixup in exynos_hdmi.c
- vc4_crtc_mode_fixup and vc4_dpi_encoder_mode_fixup (they both just check
  for interlaced modes, we could probably dump the same check in
  connector->mode_valid).

Plus the 2 bridge drivers. Everyone else does either something more
complex, or something that's not quite correct.
-Daniel

> 
> Thanks, Daniel
> 
> > ---
> >  drivers/gpu/drm/arc/arcpgu_crtc.c | 39 ++++++++++++++++++++++++---------------
> >  1 file changed, 24 insertions(+), 15 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/arc/arcpgu_crtc.c b/drivers/gpu/drm/arc/arcpgu_crtc.c
> > index ad9a959..01cae0a 100644
> > --- a/drivers/gpu/drm/arc/arcpgu_crtc.c
> > +++ b/drivers/gpu/drm/arc/arcpgu_crtc.c
> > @@ -32,6 +32,18 @@
> >  	{ "r8g8b8", 24, {16, 8}, {8, 8}, {0, 8}, {0, 0}, DRM_FORMAT_RGB888 },
> >  };
> >  
> > +static bool arc_pgu_is_mode_valid(struct arcpgu_drm_private *arcpgu,
> > +				  const struct drm_display_mode *mode)
> > +{
> > +	long rate, clk_rate = mode->clock * 1000;
> > +
> > +	rate = clk_round_rate(arcpgu->clk, clk_rate);
> > +	if (rate != clk_rate)
> > +		return false;
> > +
> > +	return true;
> > +}
> > +
> >  static void arc_pgu_set_pxl_fmt(struct drm_crtc *crtc)
> >  {
> >  	struct arcpgu_drm_private *arcpgu = crtc_to_arcpgu_priv(crtc);
> > @@ -64,6 +76,17 @@ static void arc_pgu_set_pxl_fmt(struct drm_crtc *crtc)
> >  	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
> >  };
> >  
> > +enum drm_mode_status arc_pgu_crtc_mode_valid(struct drm_crtc *crtc,
> > +					     const struct drm_display_mode *mode)
> > +{
> > +	struct arcpgu_drm_private *arcpgu = crtc_to_arcpgu_priv(crtc);
> > +
> > +	if (!arc_pgu_is_mode_valid(arcpgu, mode))
> > +		return MODE_NOCLOCK;
> > +
> > +	return MODE_OK;
> > +}
> > +
> >  static void arc_pgu_crtc_mode_set_nofb(struct drm_crtc *crtc)
> >  {
> >  	struct arcpgu_drm_private *arcpgu = crtc_to_arcpgu_priv(crtc);
> > @@ -129,20 +152,6 @@ static void arc_pgu_crtc_disable(struct drm_crtc *crtc)
> >  			      ~ARCPGU_CTRL_ENABLE_MASK);
> >  }
> >  
> > -static int arc_pgu_crtc_atomic_check(struct drm_crtc *crtc,
> > -				     struct drm_crtc_state *state)
> > -{
> > -	struct arcpgu_drm_private *arcpgu = crtc_to_arcpgu_priv(crtc);
> > -	struct drm_display_mode *mode = &state->adjusted_mode;
> > -	long rate, clk_rate = mode->clock * 1000;
> > -
> > -	rate = clk_round_rate(arcpgu->clk, clk_rate);
> > -	if (rate != clk_rate)
> > -		return -EINVAL;
> > -
> > -	return 0;
> > -}
> > -
> >  static void arc_pgu_crtc_atomic_begin(struct drm_crtc *crtc,
> >  				      struct drm_crtc_state *state)
> >  {
> > @@ -158,6 +167,7 @@ static void arc_pgu_crtc_atomic_begin(struct drm_crtc *crtc,
> >  }
> >  
> >  static const struct drm_crtc_helper_funcs arc_pgu_crtc_helper_funcs = {
> > +	.mode_valid	= arc_pgu_crtc_mode_valid,
> >  	.mode_set	= drm_helper_crtc_mode_set,
> >  	.mode_set_base	= drm_helper_crtc_mode_set_base,
> >  	.mode_set_nofb	= arc_pgu_crtc_mode_set_nofb,
> > @@ -165,7 +175,6 @@ static void arc_pgu_crtc_atomic_begin(struct drm_crtc *crtc,
> >  	.disable	= arc_pgu_crtc_disable,
> >  	.prepare	= arc_pgu_crtc_disable,
> >  	.commit		= arc_pgu_crtc_enable,
> > -	.atomic_check	= arc_pgu_crtc_atomic_check,
> >  	.atomic_begin	= arc_pgu_crtc_atomic_begin,
> >  };
> >  
> > -- 
> > 1.9.1
> > 
> > 
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch