linux-kernel - Re: [PATCH] drm: bridge: samsung-dsim: Don't use FORCE_STOP

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Message-ID: <25f0cdf7305eac946629895179be8f2b@kernel.org>
Date: Tue, 30 Jan 2024 10:24:00 +0100
From: Michael Walle <mwalle@...nel.org>
To: Dario Binacchi <dario.binacchi@...rulasolutions.com>
Cc: Dave Airlie <airlied@...il.com>, Dmitry Osipenko
 <dmitry.osipenko@...labora.com>, Inki Dae <daeinki@...il.com>, Neil
 Armstrong <neil.armstrong@...aro.org>, Laurent Pinchart
 <Laurent.pinchart@...asonboard.com>, Robert Foss <rfoss@...nel.org>, Frieder
 Schrempf <frieder.schrempf@...tron.de>, Jagan Teki
 <jagan@...rulasolutions.com>, Andrzej Hajda <andrzej.hajda@...el.com>, Marek
 Szyprowski <m.szyprowski@...sung.com>, Jonas Karlman <jonas@...boo.se>,
 Jernej Skrabec <jernej.skrabec@...il.com>, Tim Harvey
 <tharvey@...eworks.com>, Alexander Stein <alexander.stein@...tq-group.com>,
 linux-kernel@...r.kernel.org, DRI mailing list
 <dri-devel@...ts.freedesktop.org>, Daniel Vetter <daniel@...ll.ch>, Michael
 Trimarchi <michael@...rulasolutions.com>
Subject: Re: [PATCH] drm: bridge: samsung-dsim: Don't use FORCE_STOP_STATE

Hi Dario,

>> >> Just FYI this conflictted pretty heavily with drm-misc-next changes in
>> >> the same area, someone should check drm-tip has the correct
>> >> resolution, I'm not really sure what is definitely should be.
>> >
>> > FWIW, this looks rather messy now. The drm-tip doesn't build.
>> >
>> > There was a new call to samsung_dsim_set_stop_state() introduced
>> > in commit b2fe2292624ac (drm: bridge: samsung-dsim: enter display
>> > mode in the enable() callback).
>> 
>> I had a closer look at the latest linux-next (where somehow my patch
>> made it into) and tried to apply commit b2fe2292624ac (drm: bridge:
>> samsung-dsim: enter display mode in the enable() callback). It looks
>> like only the following hunk is still needed from that patch. 
>> Everything
>> else is covered by this fixes patch.
>> 
>> Dario, could you rebase your commit onto this patch? I had a quick 
>> test
>> with this change and it seems to work fine for our case.
>> 
>> --snip--
>> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
>> b/drivers/gpu/drm/bridge/samsung-dsim.c
>> index 63a1a0c88be4..92755c90e7d2 100644
>> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
>> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
>> @@ -1498,6 +1498,8 @@ static void samsung_dsim_atomic_disable(struct
>> drm_bridge *bridge,
>>          if (!(dsi->state & DSIM_STATE_ENABLED))
>>                  return;
>> 
>> +       samsung_dsim_set_display_enable(dsi, false);
>> +
>>          dsi->state &= ~DSIM_STATE_VIDOUT_AVAILABLE;
>>   }
>> 
>> @@ -1506,8 +1508,6 @@ static void
>> samsung_dsim_atomic_post_disable(struct drm_bridge *bridge,
>>   {
>>          struct samsung_dsim *dsi = bridge_to_dsi(bridge);
>> 
>> -       samsung_dsim_set_display_enable(dsi, false);
>> -
>>          dsi->state &= ~DSIM_STATE_ENABLED;
>>          pm_runtime_put_sync(dsi->dev);
>>   }
>> --snip--
>> 
>> -michael
> 
> I'm sorry, but I didn't understand well what I have to do.

Basically, just rebase your patch (drm: bridge: samsung-dsim:
enter display mode in the enable() callback) on top of
linux-next.

> This is what I have done:
> 
> git clone 
> https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next.git
> cd linux-next
> # add your changes, the ones of the emails
> git am --reject 
> 0001-drm-bridge-samsung-dsim-enter-display-mode-in-the-en.patch
> 
> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
> b/drivers/gpu/drm/bridge/samsung-dsim.c
> index 92755c90e7d2..b47929072583 100644
> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> @@ -1508,6 +1508,9 @@ static void
> samsung_dsim_atomic_post_disable(struct drm_bridge *bridge,
>  {
>         struct samsung_dsim *dsi = bridge_to_dsi(bridge);
> 
> +       if (!samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type))
> +               samsung_dsim_set_stop_state(dsi, true);
> +

This one should be removed. There is no stop state anymore.
With that hunk, it doesn't compile anyway.

>         dsi->state &= ~DSIM_STATE_ENABLED;
>         pm_runtime_put_sync(dsi->dev);
>  }
> 
> And then test the driver for my use case.

Yes. The hunk I've posted above, should be all what's left
of your patch, because as far as I see it, most of your changes
are already contained in my fixes patch. What's left is that
you disable the video mode in .disable() and not in
post_disable().

-michael