6.5-rc1 breakage in samsung-dsim

[Marek Vasut]

On 7/12/23 20:52, Tim Harvey wrote:
> Greetings,

Tim,

> I've noticed a regression in 6.5-rc1 that I'm having trouble bisecting
> between 6.4 with regards to imx8mm MIPI DSI.
> 
> I'm testing on an imx8mm-venice-gw72xx-0x with the following display:
>   - Powertip PH800480T013-IDF02 compatible panel
>   - Toshiba TC358762 compatible DSI to DBI bridge
>   - ATTINY based regulator used for backlight controller and panel enable

You mean RPi 7" display wired to non-RPi hardware like many people do ? ;-)

> I'm using a dt overlay to support this [1] which works on 6.4 but on
> 6.5-rc1 I get the following error:
> [    6.110585] samsung-dsim 32e60000.dsi: xfer timed out: 29 06 00 00
> 64 01 05 00 00 00
> [    6.326588] tc358762 32e60000.dsi.0: error initializing bridge (-110)
> 
> I'm trying to bisect this for some reason. Does anyone have any idea
> what may be causing this or how I can debug it?

Try and do something like ...

git revert --no-edit v6.4..v6.5-rc1 -- drivers/gpu/drm/bridge/tc358762.c 
drivers/gpu/drm/bridge/samsung-dsim.c drivers/regulator/*attiny*.c

(I might have the filenames wrong)

Does that start working afterward ?

If so, you can reverse-bisect on the reverts.

I wouldn't be surprised if this was somehow related to the non-burst 
mode delay calculation again, sigh.

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