From: Boris Brezillon <boris.brezillon@collabora.com>
To: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Swapnil Jakhade <sjakhade@cadence.com>,
Sekhar Nori <nsekhar@ti.com>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
dri-devel@lists.freedesktop.org,
Nikhil Devshatwar <nikhil.nd@ti.com>
Subject: Re: [PATCH 3/5] drm: bridge: Propagate the bus flags from bridge->timings
Date: Fri, 30 Oct 2020 09:50:48 +0100 [thread overview]
Message-ID: <20201030095048.2026d1d1@collabora.com> (raw)
In-Reply-To: <def32047-de38-d50f-8fd9-31e4dcfe56b9@ti.com>
On Fri, 30 Oct 2020 10:40:46 +0200
Tomi Valkeinen <tomi.valkeinen@ti.com> wrote:
> Hi Boris,
>
> On 30/10/2020 10:08, Boris Brezillon wrote:
> > The "propagate output flags" and soon to be added "use
> > timing->input_flags if present" logic should only be used as a fallback
> > for bridges that do not support dynamic bus format/flags negotiation
> > IMHO. Ideally we'd want to convert all bridges to do this dynamic bus
> > format/flags negotiation and get rid of timings->input_bus_flags once
> > this is done, but that's likely to take time. So, if your driver
> > implements the ->atomic_check() hook and needs specific input flags,
> > I'd recommend setting the input flags there instead of specifying it
> > through timings->input_bus_flags.
>
> What is bus flags negotiation? Don't we have negotiation only for bus formats? Bus flags are just
> set, and the previous bridge in the chain has to use those flags.
Well, there's currently no such negotiation, but I don't see why there
wouldn't be one at some point if bridges can configure it dynamically
(in you A -> B example, A output flags must match B input flags, and if
both A and B can configure those dynamically, they need to negotiate
that part too).
>
> Or do you just refer to setting the bus flags dynamically in atomic_check, versus static in
> input_bus_flags?
Yes, that's what I suggest, even if those flags are static right now.
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next prev parent reply other threads:[~2020-10-30 8:50 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-16 10:39 [PATCH 0/5] drm/tidss: Use new connector model for tidss Nikhil Devshatwar
2020-10-16 10:39 ` [PATCH 1/5] drm/tidss: Move to newer connector model Nikhil Devshatwar
2020-10-21 7:47 ` Tomi Valkeinen
2020-10-29 22:54 ` Laurent Pinchart
2020-10-16 10:39 ` [PATCH 2/5] drm/tidss: Set bus_format correctly from bridge/connector Nikhil Devshatwar
2020-10-29 22:57 ` Laurent Pinchart
2020-11-09 11:40 ` Nikhil Devshatwar
2020-10-16 10:39 ` [PATCH 3/5] drm: bridge: Propagate the bus flags from bridge->timings Nikhil Devshatwar
2020-10-21 11:31 ` Tomi Valkeinen
2020-10-28 14:34 ` Nikhil Devshatwar
2020-10-29 22:48 ` Laurent Pinchart
2020-10-30 7:30 ` Tomi Valkeinen
2020-10-30 8:08 ` Boris Brezillon
2020-10-30 8:40 ` Tomi Valkeinen
2020-10-30 8:50 ` Boris Brezillon [this message]
2020-10-16 10:39 ` [PATCH 4/5] drm/bridge: tfp410: Support format negotiation Nikhil Devshatwar
2020-10-29 22:31 ` Laurent Pinchart
2020-10-16 10:39 ` [PATCH 5/5] drm/bridge: mhdp8564: " Nikhil Devshatwar
2020-10-28 14:40 ` Swapnil Kashinath Jakhade
2020-10-29 22:39 ` Laurent Pinchart
2020-11-02 7:25 ` Tomi Valkeinen
2020-10-19 12:11 ` [PATCH 0/5] drm/tidss: Use new connector model for tidss Tomi Valkeinen
2020-10-28 14:19 ` Nikhil Devshatwar
2020-10-29 7:14 ` Tomi Valkeinen
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