linux-kernel - Re: [PATCH 0/2] pwm: mtk-disp: Fix backlight configuration at boot

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Message-ID: <87h6wdxqh5.fsf@collabora.com>
Date:   Thu, 26 Jan 2023 17:31:02 +0200
From:   Adrian Ratiu <adrian.ratiu@...labora.com>
To:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
Cc:     u.kleine-koenig@...gutronix.de, matthias.bgg@...il.com,
        weiqing.kong@...iatek.com, jitao.shi@...iatek.com,
        linux-pwm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org,
        kernel@...labora.com, thierry.reding@...il.com
Subject: Re: [PATCH 0/2] pwm: mtk-disp: Fix backlight configuration at boot

On Mon, 23 Jan 2023, AngeloGioacchino Del Regno 
<angelogioacchino.delregno@...labora.com> wrote:
> Since the pwm-mtk-disp driver was fixed to get PWM_EN state from 
> the right register, an old two-wrongs-make-one-right issue 
> emerged: as a result, MT8192 Asurada Spherion got no backlight 
> at boot unless a suspend/resume cycle was performed.  Also, the 
> backlight would sometimes not get updated with the requested 
> value, requiring the user to change it back and forth until it 
> worked. 
> 
> This series fixes both of the aforementioned issues found on 
> MT8192. 

Thanks for the series. This also improves backlight on MT8183.

I've been testing using the panfrost driver on a ChromiumOS 
userspace on a jacuzzi board and I've had issues like the screen 
going blank then not coming back, which these patches appear to 
solve. Many thanks!

Tested-by: Adrian Ratiu <adrian.ratiu@...labora.com>

>
> AngeloGioacchino Del Regno (2):
>   pwm: mtk-disp: Disable shadow registers before setting backlight
>     values
>   pwm: mtk-disp: Configure double buffering before reading in
>     .get_state()
>
>  drivers/pwm/pwm-mtk-disp.c | 34 +++++++++++++++++++++++-----------
>  1 file changed, 23 insertions(+), 11 deletions(-)
>
> -- 
> 2.39.0