linux-kernel - Re: [PATCH 4/4] drm/sun4i: Enable DRM InfoFrame support on H6

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Message-ID: <CAGb2v67T-nOqxkjekcc1ze9otVrzJb5KEtdJuMMk+dEGgAn1pQ@mail.gmail.com>
Date:   Tue, 25 Jun 2019 00:07:23 +0800
From:   Chen-Yu Tsai <wens@...e.org>
To:     Jernej Škrabec <jernej.skrabec@...l.net>
Cc:     Andrzej Hajda <a.hajda@...sung.com>,
        Jonas Karlman <jonas@...boo.se>,
        "Laurent.pinchart@...asonboard.com" 
        <Laurent.pinchart@...asonboard.com>,
        "narmstrong@...libre.com" <narmstrong@...libre.com>,
        "khilman@...libre.com" <khilman@...libre.com>,
        "zhengyang@...k-chips.com" <zhengyang@...k-chips.com>,
        "maxime.ripard@...tlin.com" <maxime.ripard@...tlin.com>,
        "hjc@...k-chips.com" <hjc@...k-chips.com>,
        "heiko@...ech.de" <heiko@...ech.de>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 4/4] drm/sun4i: Enable DRM InfoFrame support on H6

On Tue, Jun 25, 2019 at 12:03 AM Jernej Škrabec <jernej.skrabec@...l.net> wrote:
>
> Dne ponedeljek, 24. junij 2019 ob 17:56:30 CEST je Chen-Yu Tsai napisal(a):
> > On Mon, Jun 24, 2019 at 11:49 PM Andrzej Hajda <a.hajda@...sung.com> wrote:
> > > On 24.06.2019 17:05, Jernej Škrabec wrote:
> > > > Dne ponedeljek, 24. junij 2019 ob 17:03:31 CEST je Andrzej Hajda
> napisal(a):
> > > >> On 26.05.2019 23:20, Jonas Karlman wrote:
> > > >>> This patch enables Dynamic Range and Mastering InfoFrame on H6.
> > > >>>
> > > >>> Cc: Maxime Ripard <maxime.ripard@...tlin.com>
> > > >>> Cc: Jernej Skrabec <jernej.skrabec@...l.net>
> > > >>> Signed-off-by: Jonas Karlman <jonas@...boo.se>
> > > >>> ---
> > > >>>
> > > >>>  drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c | 2 ++
> > > >>>  drivers/gpu/drm/sun4i/sun8i_dw_hdmi.h | 1 +
> > > >>>  2 files changed, 3 insertions(+)
> > > >>>
> > > >>> diff --git a/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c
> > > >>> b/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c index
> > > >>> 39d8509d96a0..b80164dd8ad8
> > > >>> 100644
> > > >>> --- a/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c
> > > >>> +++ b/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c
> > > >>> @@ -189,6 +189,7 @@ static int sun8i_dw_hdmi_bind(struct device *dev,
> > > >>> struct device *master,>
> > > >>>
> > > >>>     sun8i_hdmi_phy_init(hdmi->phy);
> > > >>>
> > > >>>     plat_data->mode_valid = hdmi->quirks->mode_valid;
> > > >>>
> > > >>> +   plat_data->drm_infoframe = hdmi->quirks->drm_infoframe;
> > > >>>
> > > >>>     sun8i_hdmi_phy_set_ops(hdmi->phy, plat_data);
> > > >>>
> > > >>>     platform_set_drvdata(pdev, hdmi);
> > > >>>
> > > >>> @@ -255,6 +256,7 @@ static const struct sun8i_dw_hdmi_quirks
> > > >>> sun8i_a83t_quirks = {>
> > > >>>
> > > >>>  static const struct sun8i_dw_hdmi_quirks sun50i_h6_quirks = {
> > > >>>
> > > >>>     .mode_valid = sun8i_dw_hdmi_mode_valid_h6,
> > > >>>
> > > >>> +   .drm_infoframe = true,
> > > >>>
> > > >>>  };
> > > >>>
> > > >>>  static const struct of_device_id sun8i_dw_hdmi_dt_ids[] = {
> > > >>>
> > > >>> diff --git a/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.h
> > > >>> b/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.h index
> > > >>> 720c5aa8adc1..2a0ec08ee236
> > > >>> 100644
> > > >>> --- a/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.h
> > > >>> +++ b/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.h
> > > >>> @@ -178,6 +178,7 @@ struct sun8i_dw_hdmi_quirks {
> > > >>>
> > > >>>     enum drm_mode_status (*mode_valid)(struct drm_connector
> > > >
> > > > *connector,
> > > >
> > > >>>                                        const struct
> > > >
> > > > drm_display_mode *mode);
> > > >
> > > >>>     unsigned int set_rate : 1;
> > > >>>
> > > >>> +   unsigned int drm_infoframe : 1;
> > > >>
> > > >> Again, drm_infoframe suggests it contains inforframe, but in fact it
> > > >> just informs infoframe can be used, so again my suggestion
> > > >> use_drm_infoframe.
> > > >>
> > > >> Moreover bool type seems more appropriate here.
> > > >
> > > > checkpatch will give warning if bool is used.
> > >
> > > Then I would say "fix/ignore checkpatch" :)
> > >
> > > But maybe there is a reason.
> >
> > Here's an old one from Linus: https://lkml.org/lkml/2013/9/1/154
> >
> > I'd say that bool in a struct is a waste of space compared to a 1 bit
> > bitfield, especially when there already are other bitfields in the same
> > struct.
> > > Anyway I've tested and I do not see the warning, could you elaborate it.
> >
> > Maybe checkpatch.pl --strict?
>
> It seems they removed that check:
> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?
> id=7967656ffbfa493f5546c0f1
>
> After reading that block of text, I'm not sure what would be prefered way for
> this case.

This:

+If a structure has many true/false values, consider consolidating them into a
+bitfield with 1 bit members, or using an appropriate fixed width type, such as
+u8.

would suggest using a bitfield, or flags within a fixed width type?

ChenYu