Re: drm dsi2hdmi bridge - temperature sensor

Re: drm dsi2hdmi bridge - temperature sensor

[Rob Clark via dri-devel]

I mean, I guess it should be possible with an ugly non-upstreamable
hack, maybe using a notifier_chain to call from the temp sensor driver
to the hdmi bridge driver.  I'm not really sure how that could be
represented cleanly in dt, maybe Rob Herring or someone else on
dri-devel has some ideas.

(Background is to not enable the display until temp is within an
acceptable range, and disable it if it goes out of range, to prevent
hw damage I guess)


BR,
-R

On Thu, Feb 14, 2019 at 7:32 AM Vinay Simha B N <simhavcs@gmail.com> wrote:
>
> rob,
>
> i am not getting much inputs in the freenode / dr-devel/irc forum.
>
> please suggest some inputs.
>
> In the interrupt handler of temperature sensor is it possible to control the drm bridge/encoder(adv7511) status to enable and disable?
>
> any other better approach to handle this scenario?
>
> --
> regards,
> vinaysimha
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Re: drm dsi2hdmi bridge - temperature sensor

[Rob Herring via dri-devel]

On Thu, Feb 14, 2019 at 9:27 AM Rob Clark <robdclark@gmail.com> wrote:
>
> I mean, I guess it should be possible with an ugly non-upstreamable
> hack, maybe using a notifier_chain to call from the temp sensor driver
> to the hdmi bridge driver.  I'm not really sure how that could be
> represented cleanly in dt, maybe Rob Herring or someone else on
> dri-devel has some ideas.
>
> (Background is to not enable the display until temp is within an
> acceptable range, and disable it if it goes out of range, to prevent
> hw damage I guess)

The thermal framework already has support for temperature trip points
triggering "throttlers". I guess the display could be a throttling
device. Really, why wouldn't you just shutdown? Seems like a strange
usecase to keep running with the display going on and off based on
temperature.

Rob

>
>
> BR,
> -R
>
> On Thu, Feb 14, 2019 at 7:32 AM Vinay Simha B N <simhavcs@gmail.com> wrote:
> >
> > rob,
> >
> > i am not getting much inputs in the freenode / dr-devel/irc forum.
> >
> > please suggest some inputs.
> >
> > In the interrupt handler of temperature sensor is it possible to control the drm bridge/encoder(adv7511) status to enable and disable?
> >
> > any other better approach to handle this scenario?
> >
> > --
> > regards,
> > vinaysimha
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Re: drm dsi2hdmi bridge - temperature sensor

[Vinay Simha B N via dri-devel]

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On Fri, 15 Feb 2019 at 1:15 AM, Rob Herring <robh@kernel.org> wrote:

> On Thu, Feb 14, 2019 at 9:27 AM Rob Clark <robdclark@gmail.com> wrote:
> >
> > I mean, I guess it should be possible with an ugly non-upstreamable
> > hack, maybe using a notifier_chain to call from the temp sensor driver
> > to the hdmi bridge driver.  I'm not really sure how that could be
> > represented cleanly in dt, maybe Rob Herring or someone else on
> > dri-devel has some ideas.
> >
> > (Background is to not enable the display until temp is within an
> > acceptable range, and disable it if it goes out of range, to prevent
> > hw damage I guess)
>
> The thermal framework already has support for temperature trip points
> triggering "throttlers". I guess the display could be a throttling
> device. Really, why wouldn't you just shutdown? Seems like a strange
> usecase to keep running with the display going on and off based on
> temperature.
>
We do not want to shutdown the system , since it’s temp threshold is up to
-30 deg c , since display(adv7533) is upto -10 deg c, will control
enable/disable based on temp range, otherwise life of the adv chip goes
down and may not be operated later.

>
> Rob
>
> >
> >
> > BR,
> > -R
> >
> > On Thu, Feb 14, 2019 at 7:32 AM Vinay Simha B N <simhavcs@gmail.com>
> wrote:
> > >
> > > rob,
> > >
> > > i am not getting much inputs in the freenode / dr-devel/irc forum.
> > >
> > > please suggest some inputs.
> > >
> > > In the interrupt handler of temperature sensor is it possible to
> control the drm bridge/encoder(adv7511) status to enable and disable?
> > >
> > > any other better approach to handle this scenario?
> > >
> > > --
> > > regards,
> > > vinaysimha
>
-- 
regards,
vinaysimha

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Re: drm dsi2hdmi bridge - temperature sensor

[Sam Ravnborg]

Hi Rob.

> >
> > (Background is to not enable the display until temp is within an
> > acceptable range, and disable it if it goes out of range, to prevent
> > hw damage I guess)
> 
> The thermal framework already has support for temperature trip points
> triggering "throttlers". I guess the display could be a throttling
> device. Really, why wouldn't you just shutdown? Seems like a strange
> usecase to keep running with the display going on and off based on
> temperature.

(Jumping into the middle of a discussion here, and maybe I got it wrong)

For the devices I work with a shutdown would be highly unexpected
just because something insignificant like the display fails to work.
The devices are used to control the climate for birds, sometimes in hot areas.
We do not want the device to shut down and let emergency take over,
due to a non-functional display.

	Sam
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Re: drm dsi2hdmi bridge - temperature sensor

[Vinay Simha B N]

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rob,

hpd works in kernel 5.0.0-rc6, i.e postboot if we connect hdmi display
comes(apq8016).

added the temperature alert_handler in adv7511_drv.c
in adv7511_detect , i had set status = connector_status_disconnected; ,
since display should not come initially,
but when irq calls
schedule_work(&adv7511->hpd_work)/ adv7511_irq_process(adv7511, true); in
temp_alert_handler , hdmi display does not comes
[drm] Cannot find any crtc or sizes

any suggestion on how to initially not switch on the hdmi display and later
enable when irq from temp alert.

On Fri, Feb 15, 2019 at 1:24 AM Sam Ravnborg <sam@ravnborg.org> wrote:

> Hi Rob.
>
> > >
> > > (Background is to not enable the display until temp is within an
> > > acceptable range, and disable it if it goes out of range, to prevent
> > > hw damage I guess)
> >
> > The thermal framework already has support for temperature trip points
> > triggering "throttlers". I guess the display could be a throttling
> > device. Really, why wouldn't you just shutdown? Seems like a strange
> > usecase to keep running with the display going on and off based on
> > temperature.
>
> (Jumping into the middle of a discussion here, and maybe I got it wrong)
>
> For the devices I work with a shutdown would be highly unexpected
> just because something insignificant like the display fails to work.
> The devices are used to control the climate for birds, sometimes in hot
> areas.
> We do not want the device to shut down and let emergency take over,
> due to a non-functional display.
>
>         Sam
>


-- 
regards,
vinaysimha

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