From: Daniel Stone <daniel@fooishbar.org>
To: Esaki Tomohito <etom@igel.co.jp>
Cc: linux-renesas-soc@vger.kernel.org,
dri-devel@lists.freedesktop.org,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Subject: Re: [PATCH] drm: rcar-du: add modifiers support
Date: Tue, 30 Nov 2021 13:20:48 +0000 [thread overview]
Message-ID: <CAPj87rPjCtXLtsfh2V=rPo_tcAQC64cWJXu89qCNb+iQCi1Wag@mail.gmail.com> (raw)
In-Reply-To: <6b27be2c-9b13-38ef-ca6a-77c986757386@igel.co.jp>
Hi Esaki-san,
On Tue, 30 Nov 2021 at 08:44, Esaki Tomohito <etom@igel.co.jp> wrote:
> On 2021/11/18 23:05, Laurent Pinchart wrote:
> > On Thu, Nov 18, 2021 at 01:02:11PM +0000, Daniel Stone wrote:
> >> Laurent's concern is that the DRM core should handle this rather than
> >> open-coding in every driver, which I agree with. Some drivers (e.g.
> >> radeon, maybe legacy NV?) do not support modifiers, and _also_ do
> >> magic inference of the actual layout of the underlying buffer.
> >> However, these drivers are legacy and we do not accept any new
> >> addition of inferring layout without modifiers.
> >>
> >> I think the best way forward here is:
> >> - add a new mode_config.cannot_support_modifiers flag, and enable
> >> this in radeon (plus any other drivers in the same boat)
> >
> > Is there an easy way to identify the drivers that need this ?
>
> Should I find a driver that has not use drm_plane_funcs?
I don't think there's a good way to systematically audit it. The only
two I know are radeon (i.e. pre-amdgpu) and nouveau (pre-nv50), both
of which pass no modifiers to drm_universal_plane_init(), but do have
magic back channels to communicate tiling information. If anyone knows
of any others, well, I guess we'll find out. :)
> >> - change drm_universal_plane_init() to advertise the LINEAR modifier
> >> when NULL is passed as the modifier list (including installing a
> >> default .format_mod_supported hook)
... except when cannot_support_modifiers is set.
> >> - remove the mode_config.allow_fb_modifiers hook and always
> >> advertise modifier support, unless
> >> mode_config.cannot_support_modifiers is set
> >
> > Looks good to me.
>
> I agree with this way, I'll try to create a patches.
Thanks a lot! :)
Cheers,
Daniel
next prev parent reply other threads:[~2021-11-30 13:21 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-09 5:45 [PATCH] drm: rcar-du: add modifiers support Tomohito Esaki
2019-05-09 7:14 ` Laurent Pinchart
2019-05-09 9:25 ` Esaki Tomohito
2019-05-11 18:10 ` Laurent Pinchart
2019-05-17 7:45 ` Esaki Tomohito
2021-11-18 12:31 ` Laurent Pinchart
2021-11-18 13:02 ` Daniel Stone
2021-11-18 14:05 ` Laurent Pinchart
2021-11-30 8:44 ` Esaki Tomohito
2021-11-30 13:20 ` Daniel Stone [this message]
2021-12-01 5:47 ` Esaki Tomohito
2021-11-24 2:49 ` Esaki Tomohito
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