2015-02-13 04:07:55

by Stephen Boyd

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Subject: Re: [PATCH v2 2/2] leds: add Qualcomm PM8941 WLED driver

On 01/29/15 04:48, Ivan T. Ivanov wrote:
>
> Otherwise it looks good. Driver is loaded and device is detected
> properly (i have added readings for type and subtype registers).
> Do you know where I can measure result from changing brightness
> sysfs entry. I am using 8074 dragonboard?

Does the backlight turn on? From what I can tell it controls the
backlight, but it may be that nothings getting displayed so it won't be
noticeable.

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Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project


2015-02-13 04:29:10

by Ivan T. Ivanov

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Subject: Re: [PATCH v2 2/2] leds: add Qualcomm PM8941 WLED driver


On Thu, 2015-02-12 at 20:07 -0800, Stephen Boyd wrote:
> On 01/29/15 04:48, Ivan T. Ivanov wrote:
> > Otherwise it looks good. Driver is loaded and device is detected
> > properly (i have added readings for type and subtype registers).
> > Do you know where I can measure result from changing brightness
> > sysfs entry. I am using 8074 dragonboard?
>
> Does the backlight turn on? From what I can tell it controls the
> backlight, but it may be that nothings getting displayed so it won't be
> noticeable.
>

Yes, I can not see visual changes. That is why I have asked where
I could hook the probe and measure current change or wherever.
BL_WLEDx signals go out from J2, but somehow I was unable to
locate it on the board, will try to look harder :-)

Regards,
Ivan

2015-02-13 04:34:24

by Stephen Boyd

[permalink] [raw]
Subject: Re: [PATCH v2 2/2] leds: add Qualcomm PM8941 WLED driver

On 02/12/15 20:28, Ivan T. Ivanov wrote:
> On Thu, 2015-02-12 at 20:07 -0800, Stephen Boyd wrote:
>> On 01/29/15 04:48, Ivan T. Ivanov wrote:
>>> Otherwise it looks good. Driver is loaded and device is detected
>>> properly (i have added readings for type and subtype registers).
>>> Do you know where I can measure result from changing brightness
>>> sysfs entry. I am using 8074 dragonboard?
>> Does the backlight turn on? From what I can tell it controls the
>> backlight, but it may be that nothings getting displayed so it won't be
>> noticeable.
>>
> Yes, I can not see visual changes. That is why I have asked where
> I could hook the probe and measure current change or wherever.
> BL_WLEDx signals go out from J2, but somehow I was unable to
> locate it on the board, will try to look harder :-)
>
>

When the screen is "off" in android I can still turn on the brightness
to max in sysfs and see the screen glow. Hopefully we don't need
something else to make that work.

--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

2015-02-17 23:05:59

by Bjorn Andersson

[permalink] [raw]
Subject: Re: [PATCH v2 2/2] leds: add Qualcomm PM8941 WLED driver

On Thu, Feb 12, 2015 at 8:07 PM, Stephen Boyd <[email protected]> wrote:
> On 01/29/15 04:48, Ivan T. Ivanov wrote:
>>
>> Otherwise it looks good. Driver is loaded and device is detected
>> properly (i have added readings for type and subtype registers).
>> Do you know where I can measure result from changing brightness
>> sysfs entry. I am using 8074 dragonboard?
>
> Does the backlight turn on? From what I can tell it controls the
> backlight, but it may be that nothings getting displayed so it won't be
> noticeable.
>

I have not measured the voltage/current, nor have had something on the
display. But on the various devices I've tested (Xperia Z1 & Xperia Z
Ultra) the backlight is clearly on.

Regards,
Bjorn