Date:   Wed, 24 Oct 2018 10:23:40 +0200
From:   Lucas Stach <l.stach@...gutronix.de>
To:     Daniel Vetter <daniel@...ll.ch>,
        Benjamin Gaignard <benjamin.gaignard@...aro.org>
Cc:     sean@...rly.run, Benjamin GAIGNARD <benjamin.gaignard@...com>,
        David Airlie <airlied@...ux.ie>,
        Philippe Cornu <philippe.cornu@...com>,
        ML dri-devel <dri-devel@...ts.freedesktop.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Yannick Fertre <yannick.fertre@...com>,
        Vincent Abriou <vincent.abriou@...com>
Subject: Re: [PATCH v1 1/2] drm: Add missing flags for pixel clock & data
 enable

Am Mittwoch, den 24.10.2018, 10:16 +0200 schrieb Daniel Vetter:
> On Tue, Oct 23, 2018 at 04:50:19PM +0200, Benjamin Gaignard wrote:
> > Le lun. 15 oct. 2018 à 13:15, Benjamin Gaignard
> > <benjamin.gaignard@...aro.org> a écrit :
> > > 
> > > Le lun. 24 sept. 2018 à 13:59, Yannick Fertré <yannick.fertre@...com> a écrit :
> > > > 
> > > > Add missing flags for pixel clock & data enable polarities.
> > > > These flags are similar to other synchronization signals (hsync, vsync...).
> > > > 
> > > > Signed-off-by: Yannick Fertré <yannick.fertre@...com>
> > > 
> > > Reviewed-by: Benjamin Gaignard <benjamin.gaignard@...aro.org>
> > 
> > Dave or Daniel could you give us your PoV on this patch ?
> 
> Does it work? Iirc we had some userspace chocking on new mode flags, and
> needed explicit opt-in. If that looks good (check weston, -modesetting and
> drm_hwc, that should have you covered I hope) then has my ack.

What's the use of exposing those to userspace? There are a number of
drivers that already have to deal with this and they are totally fine
with keeping this information internal to the driver.

For reference see include/video/display_timing.h, specifically the enum
display_flags.

Regards,
Lucas

> -Daniel
> 
> > Thanks
> > 
> > > 
> > > > ---
> > > >  drivers/gpu/drm/drm_modes.c | 19 ++++++++++++++++++-
> > > >  include/uapi/drm/drm_mode.h |  6 ++++++
> > > >  2 files changed, 24 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
> > > > index 02db9ac..596f8b3 100644
> > > > --- a/drivers/gpu/drm/drm_modes.c
> > > > +++ b/drivers/gpu/drm/drm_modes.c
> > > > @@ -130,7 +130,7 @@ EXPORT_SYMBOL(drm_mode_probed_add);
> > > >   * according to the hdisplay, vdisplay, vrefresh.
> > > >   * It is based from the VESA(TM) Coordinated Video Timing Generator by
> > > >   * Graham Loveridge April 9, 2003 available at
> > > > - * http://www.elo.utfsm.cl/~elo212/docs/CVTd6r1.xls
> > > > + * http://www.elo.utfsm.cl/~elo212/docs/CVTd6r1.xls
> > > >   *
> > > >   * And it is copied from xf86CVTmode in xserver/hw/xfree86/modes/xf86cvt.c.
> > > >   * What I have done is to translate it by using integer calculation.
> > > > @@ -611,6 +611,15 @@ void drm_display_mode_from_videomode(const struct videomode *vm,
> > > >                 dmode->flags |= DRM_MODE_FLAG_DBLSCAN;
> > > >         if (vm->flags & DISPLAY_FLAGS_DOUBLECLK)
> > > >                 dmode->flags |= DRM_MODE_FLAG_DBLCLK;
> > > > +       if (vm->flags & DISPLAY_FLAGS_PIXDATA_POSEDGE)
> > > > +               dmode->flags |= DRM_MODE_FLAG_PPIXCLK;
> > > > +       else if (vm->flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE)
> > > > +               dmode->flags |= DRM_MODE_FLAG_NPIXCLK;
> > > > +       if (vm->flags & DISPLAY_FLAGS_DE_HIGH)
> > > > +               dmode->flags |= DRM_MODE_FLAG_PDATAEN;
> > > > +       else if (vm->flags & DISPLAY_FLAGS_DE_LOW)
> > > > +               dmode->flags |= DRM_MODE_FLAG_NDE;
> > > > +
> > > >         drm_mode_set_name(dmode);
> > > >  }
> > > >  EXPORT_SYMBOL_GPL(drm_display_mode_from_videomode);
> > > > @@ -652,6 +661,14 @@ void drm_display_mode_to_videomode(const struct drm_display_mode *dmode,
> > > >                 vm->flags |= DISPLAY_FLAGS_DOUBLESCAN;
> > > >         if (dmode->flags & DRM_MODE_FLAG_DBLCLK)
> > > >                 vm->flags |= DISPLAY_FLAGS_DOUBLECLK;
> > > > +       if (dmode->flags & DRM_MODE_FLAG_PPIXDATA)
> > > > +               vm->flags |= DISPLAY_FLAGS_PIXDATA_POSEDGE;
> > > > +       else if (dmode->flags & DRM_MODE_FLAG_NPIXDATA)
> > > > +               vm->flags |= DISPLAY_FLAGS_PIXDATA_NEGEDGE;
> > > > +       if (dmode->flags & DRM_MODE_FLAG_PDE)
> > > > +               vm->flags |= DISPLAY_FLAGS_DE_HIGH;
> > > > +       else if (dmode->flags & DRM_MODE_FLAG_NDE)
> > > > +               vm->flags |= DISPLAY_FLAGS_DE_LOW;
> > > >  }
> > > >  EXPORT_SYMBOL_GPL(drm_display_mode_to_videomode);
> > > > 
> > > > diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
> > > > index d3e0fe3..b335a17 100644
> > > > --- a/include/uapi/drm/drm_mode.h
> > > > +++ b/include/uapi/drm/drm_mode.h
> > > > @@ -89,6 +89,12 @@ extern "C" {
> > > >  #define  DRM_MODE_FLAG_3D_TOP_AND_BOTTOM       (7<<14)
> > > >  #define  DRM_MODE_FLAG_3D_SIDE_BY_SIDE_HALF    (8<<14)
> > > > 
> > > > +/* flags for polarity clock & data enable polarities */
> > > > +#define DRM_MODE_FLAG_PPIXDATA                 (1 << 19)
> > > > +#define DRM_MODE_FLAG_NPIXDATA                 (1 << 20)
> > > > +#define DRM_MODE_FLAG_PDE                      (1 << 21)
> > > > +#define DRM_MODE_FLAG_NDE                      (1 << 22)
> > > > +
> > > >  /* Picture aspect ratio options */
> > > >  #define DRM_MODE_PICTURE_ASPECT_NONE           0
> > > >  #define DRM_MODE_PICTURE_ASPECT_4_3            1
> > > > --
> > > > 2.7.4
> > > > 
> > > > _______________________________________________
> > > > dri-devel mailing list
> > > > dri-devel@...ts.freedesktop.org
> > > > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> > 
> > 
> > 
> > -- 
> > Benjamin Gaignard
> > 
> > Graphic Study Group
> > 
> > Linaro.org │ Open source software for ARM SoCs
> > 
> > Follow Linaro: Facebook | Twitter | Blog
> 
> 

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