[0/2] pwm: mtk-disp: Fix backlight configuration at boot

  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.

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(-)
  

On Mon, 23 Jan 2023, AngeloGioacchino Del Regno 
<angelogioacchino.delregno@collabora.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@collabora.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
  

Il 23/01/23 17:06, AngeloGioacchino Del Regno ha scritto:
> 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.
> 
> 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(-)
> 

Gentle ping for this one: this is fixing backlight issues on multiple MediaTek
SoCs and was well tested.

Thanks,
Angelo
  

Il 23/02/23 15:16, AngeloGioacchino Del Regno ha scritto:
> Il 23/01/23 17:06, AngeloGioacchino Del Regno ha scritto:
>> 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.
>>
>> 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(-)
>>
> 
> Gentle ping for this one: this is fixing backlight issues on multiple MediaTek
> SoCs and was well tested.
> 
> Thanks,
> Angelo

Since this series was sent more than one month ago, and since this fixes broken
backlight on a number of Chromebooks with MT8183 and MT8192 SoCs, and seen the
urgency of getting these fixes in, I'm adding Greg to the loop.

Regards,
Angelo
  

On Wed, Mar 08, 2023 at 12:46:07PM +0100, AngeloGioacchino Del Regno wrote:
> Il 23/02/23 15:16, AngeloGioacchino Del Regno ha scritto:
> > Il 23/01/23 17:06, AngeloGioacchino Del Regno ha scritto:
> > > 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.
> > > 
> > > 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(-)
> > > 
> > 
> > Gentle ping for this one: this is fixing backlight issues on multiple MediaTek
> > SoCs and was well tested.
> > 
> > Thanks,
> > Angelo
> 
> Since this series was sent more than one month ago, and since this fixes broken
> backlight on a number of Chromebooks with MT8183 and MT8192 SoCs, and seen the
> urgency of getting these fixes in, I'm adding Greg to the loop.

$ ./scripts/get_maintainer.pl drivers/pwm/pwm-mtk-disp.c
Thierry Reding <thierry.reding@gmail.com> (maintainer:PWM SUBSYSTEM)
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de> (reviewer:PWM SUBSYSTEM)
Matthias Brugger <matthias.bgg@gmail.com> (maintainer:ARM/Mediatek SoC support)
AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> (reviewer:ARM/Mediatek SoC support)
linux-pwm@vger.kernel.org (open list:PWM SUBSYSTEM)
linux-kernel@vger.kernel.org (open list:ARM/Mediatek SoC support)
linux-arm-kernel@lists.infradead.org (moderated list:ARM/Mediatek SoC support)
linux-mediatek@lists.infradead.org (moderated list:ARM/Mediatek SoC support)

I don't see my name in there, did I become the PWM maintainer somehow?

What's wrong with Thierry taking this like normal?

thanks,

greg k-h
  

Il 08/03/23 15:50, Greg Kroah-Hartman ha scritto:
> On Wed, Mar 08, 2023 at 12:46:07PM +0100, AngeloGioacchino Del Regno wrote:
>> Il 23/02/23 15:16, AngeloGioacchino Del Regno ha scritto:
>>> Il 23/01/23 17:06, AngeloGioacchino Del Regno ha scritto:
>>>> 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.
>>>>
>>>> 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(-)
>>>>
>>>
>>> Gentle ping for this one: this is fixing backlight issues on multiple MediaTek
>>> SoCs and was well tested.
>>>
>>> Thanks,
>>> Angelo
>>
>> Since this series was sent more than one month ago, and since this fixes broken
>> backlight on a number of Chromebooks with MT8183 and MT8192 SoCs, and seen the
>> urgency of getting these fixes in, I'm adding Greg to the loop.
> 
> $ ./scripts/get_maintainer.pl drivers/pwm/pwm-mtk-disp.c
> Thierry Reding <thierry.reding@gmail.com> (maintainer:PWM SUBSYSTEM)
> "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de> (reviewer:PWM SUBSYSTEM)
> Matthias Brugger <matthias.bgg@gmail.com> (maintainer:ARM/Mediatek SoC support)
> AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> (reviewer:ARM/Mediatek SoC support)
> linux-pwm@vger.kernel.org (open list:PWM SUBSYSTEM)
> linux-kernel@vger.kernel.org (open list:ARM/Mediatek SoC support)
> linux-arm-kernel@lists.infradead.org (moderated list:ARM/Mediatek SoC support)
> linux-mediatek@lists.infradead.org (moderated list:ARM/Mediatek SoC support)
> 
> I don't see my name in there, did I become the PWM maintainer somehow?
> 
> What's wrong with Thierry taking this like normal?
> 

Nothing wrong with that. I felt like this series got ignored as I've never
received any reply from Thierry, even though it's a Fixes series that I deem
to be moderately urgent; that's why I added you to the loop.

If that created unnecessary noise, I'm extremely sorry and won't happen again.

Regards,
Angelo
  

On Wed, Mar 08, 2023 at 03:55:59PM +0100, AngeloGioacchino Del Regno wrote:
> Il 08/03/23 15:50, Greg Kroah-Hartman ha scritto:
> > On Wed, Mar 08, 2023 at 12:46:07PM +0100, AngeloGioacchino Del Regno wrote:
> > > Il 23/02/23 15:16, AngeloGioacchino Del Regno ha scritto:
> > > > Il 23/01/23 17:06, AngeloGioacchino Del Regno ha scritto:
> > > > > 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.
> > > > > 
> > > > > 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(-)
> > > > > 
> > > > 
> > > > Gentle ping for this one: this is fixing backlight issues on multiple MediaTek
> > > > SoCs and was well tested.
> > > > 
> > > > Thanks,
> > > > Angelo
> > > 
> > > Since this series was sent more than one month ago, and since this fixes broken
> > > backlight on a number of Chromebooks with MT8183 and MT8192 SoCs, and seen the
> > > urgency of getting these fixes in, I'm adding Greg to the loop.
> > 
> > $ ./scripts/get_maintainer.pl drivers/pwm/pwm-mtk-disp.c
> > Thierry Reding <thierry.reding@gmail.com> (maintainer:PWM SUBSYSTEM)
> > "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de> (reviewer:PWM SUBSYSTEM)
> > Matthias Brugger <matthias.bgg@gmail.com> (maintainer:ARM/Mediatek SoC support)
> > AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> (reviewer:ARM/Mediatek SoC support)
> > linux-pwm@vger.kernel.org (open list:PWM SUBSYSTEM)
> > linux-kernel@vger.kernel.org (open list:ARM/Mediatek SoC support)
> > linux-arm-kernel@lists.infradead.org (moderated list:ARM/Mediatek SoC support)
> > linux-mediatek@lists.infradead.org (moderated list:ARM/Mediatek SoC support)
> > 
> > I don't see my name in there, did I become the PWM maintainer somehow?
> > 
> > What's wrong with Thierry taking this like normal?
> > 
> 
> Nothing wrong with that. I felt like this series got ignored as I've never
> received any reply from Thierry, even though it's a Fixes series that I deem
> to be moderately urgent; that's why I added you to the loop.

Then ask Thierry and Uwe, what would you want to have happen if you were
the maintainer of a subsystem?

> If that created unnecessary noise, I'm extremely sorry and won't happen again.

Not noise, just confusion on my part.  I'm glad to take patches that
have no obvious maintainers, or maintainers that have disappeared, but
that doesn't seem to be the case here.

Also remember that we had the merge window, which is 2 weeks of us not
being able to take any new code at all, even for fixes.

And finally, to make it easier for your code to be accepted, please take
the time to review other's code for the subsystems you care about to
make the maintainer's load easier.  If you do that, you will often find
your patches getting faster response just by virtue of there being less
work to do on the subsystem overall.  Why not do that right now to help
out with other PWM patches?

thanks,

greg k-h
  

Il 08/03/23 16:43, Greg Kroah-Hartman ha scritto:
> On Wed, Mar 08, 2023 at 03:55:59PM +0100, AngeloGioacchino Del Regno wrote:
>> Il 08/03/23 15:50, Greg Kroah-Hartman ha scritto:
>>> On Wed, Mar 08, 2023 at 12:46:07PM +0100, AngeloGioacchino Del Regno wrote:
>>>> Il 23/02/23 15:16, AngeloGioacchino Del Regno ha scritto:
>>>>> Il 23/01/23 17:06, AngeloGioacchino Del Regno ha scritto:
>>>>>> 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.
>>>>>>
>>>>>> 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(-)
>>>>>>
>>>>>
>>>>> Gentle ping for this one: this is fixing backlight issues on multiple MediaTek
>>>>> SoCs and was well tested.
>>>>>
>>>>> Thanks,
>>>>> Angelo
>>>>
>>>> Since this series was sent more than one month ago, and since this fixes broken
>>>> backlight on a number of Chromebooks with MT8183 and MT8192 SoCs, and seen the
>>>> urgency of getting these fixes in, I'm adding Greg to the loop.
>>>
>>> $ ./scripts/get_maintainer.pl drivers/pwm/pwm-mtk-disp.c
>>> Thierry Reding <thierry.reding@gmail.com> (maintainer:PWM SUBSYSTEM)
>>> "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de> (reviewer:PWM SUBSYSTEM)
>>> Matthias Brugger <matthias.bgg@gmail.com> (maintainer:ARM/Mediatek SoC support)
>>> AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> (reviewer:ARM/Mediatek SoC support)
>>> linux-pwm@vger.kernel.org (open list:PWM SUBSYSTEM)
>>> linux-kernel@vger.kernel.org (open list:ARM/Mediatek SoC support)
>>> linux-arm-kernel@lists.infradead.org (moderated list:ARM/Mediatek SoC support)
>>> linux-mediatek@lists.infradead.org (moderated list:ARM/Mediatek SoC support)
>>>
>>> I don't see my name in there, did I become the PWM maintainer somehow?
>>>
>>> What's wrong with Thierry taking this like normal?
>>>
>>
>> Nothing wrong with that. I felt like this series got ignored as I've never
>> received any reply from Thierry, even though it's a Fixes series that I deem
>> to be moderately urgent; that's why I added you to the loop.
> 
> Then ask Thierry and Uwe, what would you want to have happen if you were
> the maintainer of a subsystem?
> 
>> If that created unnecessary noise, I'm extremely sorry and won't happen again.
> 
> Not noise, just confusion on my part.  I'm glad to take patches that
> have no obvious maintainers, or maintainers that have disappeared, but
> that doesn't seem to be the case here.
> 
> Also remember that we had the merge window, which is 2 weeks of us not
> being able to take any new code at all, even for fixes.
> 
> And finally, to make it easier for your code to be accepted, please take
> the time to review other's code for the subsystems you care about to
> make the maintainer's load easier.  If you do that, you will often find
> your patches getting faster response just by virtue of there being less
> work to do on the subsystem overall.  Why not do that right now to help
> out with other PWM patches?
> 
> thanks,
> 
> greg k-h
> 

That's right, I see the point. Will try to help as soon as I can find BW.

Thanks and sorry again,
Angelo
  

On Wed, Mar 08, 2023 at 04:43:25PM +0100, Greg Kroah-Hartman wrote:
> On Wed, Mar 08, 2023 at 03:55:59PM +0100, AngeloGioacchino Del Regno wrote:
> > Il 08/03/23 15:50, Greg Kroah-Hartman ha scritto:
> > > On Wed, Mar 08, 2023 at 12:46:07PM +0100, AngeloGioacchino Del Regno wrote:
> > > > Il 23/02/23 15:16, AngeloGioacchino Del Regno ha scritto:
> > > > > Il 23/01/23 17:06, AngeloGioacchino Del Regno ha scritto:
> > > > > > 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.
> > > > > > 
> > > > > > 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(-)
> > > > > > 
> > > > > 
> > > > > Gentle ping for this one: this is fixing backlight issues on multiple MediaTek
> > > > > SoCs and was well tested.
> > > > > 
> > > > > Thanks,
> > > > > Angelo
> > > > 
> > > > Since this series was sent more than one month ago, and since this fixes broken
> > > > backlight on a number of Chromebooks with MT8183 and MT8192 SoCs, and seen the
> > > > urgency of getting these fixes in, I'm adding Greg to the loop.
> > > 
> > > $ ./scripts/get_maintainer.pl drivers/pwm/pwm-mtk-disp.c
> > > Thierry Reding <thierry.reding@gmail.com> (maintainer:PWM SUBSYSTEM)
> > > "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de> (reviewer:PWM SUBSYSTEM)
> > > Matthias Brugger <matthias.bgg@gmail.com> (maintainer:ARM/Mediatek SoC support)
> > > AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> (reviewer:ARM/Mediatek SoC support)
> > > linux-pwm@vger.kernel.org (open list:PWM SUBSYSTEM)
> > > linux-kernel@vger.kernel.org (open list:ARM/Mediatek SoC support)
> > > linux-arm-kernel@lists.infradead.org (moderated list:ARM/Mediatek SoC support)
> > > linux-mediatek@lists.infradead.org (moderated list:ARM/Mediatek SoC support)
> > > 
> > > I don't see my name in there, did I become the PWM maintainer somehow?
> > > 
> > > What's wrong with Thierry taking this like normal?
> > > 
> > 
> > Nothing wrong with that. I felt like this series got ignored as I've never
> > received any reply from Thierry, even though it's a Fixes series that I deem
> > to be moderately urgent; that's why I added you to the loop.
> 
> Then ask Thierry and Uwe, what would you want to have happen if you were
> the maintainer of a subsystem?
> 
> > If that created unnecessary noise, I'm extremely sorry and won't happen again.
> 
> Not noise, just confusion on my part.  I'm glad to take patches that
> have no obvious maintainers, or maintainers that have disappeared, but
> that doesn't seem to be the case here.

I'm aware that there is a big backlog on PWM patches. I'm trying to
catch up but there is only so much time. Sorry this results in delays
for you (and others), I'm not happy with this situation either.

Best regards
Uwe