imx6 DM_VIDEObroken

[Tim Harvey]

On Tue, Sep 28, 2021 at 5:55 AM Anatolij Gustschin <agust at denx.de> wrote:
>
> Hey Tim,
>
> On Mon, 27 Sep 2021 17:25:58 -0700
> Tim Harvey tharvey at gateworks.com wrote:
>
> > Anatolij,
> >
> > Since commit d37618d18d49 ("imx: convert gwventana board to DM_VIDEO")
> > video support for IMX6 based Ventana boards has been broken.
>
> Back then I've tested similar DM_VIDEO conversion changes on i.mx6q
> nitrogen6q board and on i.mx6d/i.mx6s wandboards, it was okay if
> the board configuration uses the video console output during the
> boot sequence (i.e. configured to show splash screen or to output
> strings on vidconsole).
>
> > I find that while the bind function for fsl_imx6q_ipu is called the
> > probe never is (ipuv3_video_probe). Do you know why this is?
>
> Is video console output used during the boot? If not, then it
> might be the reason. With DM, the devices are probed when a subsystem
> actually tries to use them. You can try to trigger probing via
> switching to the video console output, i.e.:
>
>  => setenv stdout vidconsole

Yes, this calls ipuv3_video_probe. I guess I expected the display to
just work by default as it did before.

I looked over doc/README.console. It may be out of date as it refers
to 'video' instead of 'vidconsole'. What is the difference?

How do I get back to the state where a splash-screen is shown on the
display by default?

> >
> > I see that with commit 57f065fee2a4 ("video: ipuv3: add DM_VIDEO
> > support") you mention that DTS files must include
> > 'u-boot,dm-pre-reloc' for soc/ipu nodes to enable driver binding to
> > ipu device but I haven't been able to get that to make a difference
> > nor have I found a board that does this. You did add those props to
> > imx6qdl.dtsi at one point but they are no longer there.
>
> Does your board dts include imx6qdl-u-boot.dtsi ?
>
> The u-boot,dm-pre-reloc properties were moved to this U-Boot specific
> dtsi in 7932b1c9fdb73393aa110249c89bd426533c0649
> (imx: imx6qdl: dtsi: move U-Boot specific change to u-boot.dtsi)
>

No, I'm not including that but that is the right place for it.

Strangely, I found that if I don't have 'u-boot,dm-pre-reloc' for
soc/ipu nodes enabling video via 'setenv stdout serial,vidconsole'
works. Is there some reason why the prop is no longer required?

> > There must have been several other IMX6 boards with video support that
> > were affected by this so perhaps I'm missing something simple.
>
> I did not test it recently, it looks I'll have to do it before the
> new release.

I would think the other board maintainers would have raised a red flag
if things broke for their boards, I just haven't tested it in quite
some time for gwventana_*_defconfig.

How do you go about testing this by the way without having all the
boards and displays?

Best regards,

Tim