Re: [PATCH 2/2] drm: lcdif: Add i.MX93 LCDIF support

[Marek Vasut]

On 1/24/23 12:15, Alexander Stein wrote:
> Hi,

Hi,

> Am Dienstag, 24. Januar 2023, 08:59:39 CET schrieb Liu Ying:
> > On Mon, 2023-01-23 at 16:57 +0100, Marek Vasut wrote:
> > > On 1/23/23 08:23, Liu Ying wrote:
> > > > The LCDIF embedded in i.MX93 SoC is essentially the same to those
> > > > in i.MX8mp SoC.  However, i.MX93 LCDIF may connect with MIPI DSI
> > > > controller through LCDIF cross line pattern(controlled by mediamix
> > > > blk-ctrl) or connect with LVDS display bridge(LDB) directly or a
> > > > parallel display(also through mediamix blk-ctrl), so add multiple
> > > > encoders(with DRM_MODE_ENCODER_NONE encoder type) support in the
> > > > LCDIF DRM driver and find a bridge to attach the relevant encoder's
> > > > chain when needed.  While at it, derive lcdif_crtc_state structure
> > > > from drm_crtc_state structure to introduce bus_format and bus_flags
> > > > states so that the next downstream bridges may use consistent bus
> > > > format and bus flags.
> > >
> > > Would it be possible to split this patch into preparatory clean up
> > > and
> > > i.MX93 addition ? It seems like the patch is doing two things
> > > according
> > > to the commit message.
> >
> > IMHO, all the patch does is for i.MX93 addition, not for clean up.
> > Note that the single LCDIF embedded in i.MX93 SoC may connect with MIPI
> > DSI/LVDS/parallel related bridges to drive triple displays
> > _simultaneously_ in theory, while the three LCDIF instances embedded in
> > i.MX8mp SoC connect with MIPI DSI/LVDS/HDMI displays respectively(one
> > LCDIF maps to one display).  The multiple encoders addition and the new
> > checks for consistent bus format and bus flags are only for i.MX93
> > LCDIF, not for i.MX8mp LCDIF.  Also, I think the multiple encoders
> > addition and the new checks should be done together - if the new checks
> > come first, then the new checks do not make sense(no multiple displays
> > driven by LCDIF);
>
> You are right on this one, but on the other hand there are lot of preparing
> patches already. Even if it is useless by itself, having the bus format & flag
> checks in a separate patch, it is easier to review, IMHO.

I agree on the ease of review.

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