[Gta04-owner] Display on Debian - Was: Debian Status

[Josua Mayer]

Am 18.02.2017 um 18:14 schrieb H. Nikolaus Schaller:
>> Am 18.02.2017 um 18:03 schrieb Josua Mayer <josua.mayer97 at gmail.com>:
>>
>> Am 18.02.2017 um 17:55 schrieb Josua Mayer:
>>> Am 18.02.2017 um 17:46 schrieb H. Nikolaus Schaller:
>>>
>>>>> Am 18.02.2017 um 17:44 schrieb H. Nikolaus Schaller <hns at goldelico.com>
>>>>> :
>>>>>
>>>>>
>>>>>> Am 18.02.2017 um 17:41 schrieb Josua Mayer <josua.mayer97 at gmail.com>
>>>>>> :
>>>>>>
>>>>>>
>>>>>>>> Adding:
>>>>>>>> - display stays black. Any ideas?
>>>>>>>>
>>>>>>> Hm. This can be a lot of things. Maybe X11 config.
>>>>>>> Do you see a /sys/class/backlight entry?
>>>>>>>
>>>>>> No x11. This is a minimal cli-only system.
>>>>>> /sys/class/backlight is as empty as can be.
>>>>>> I found that there are only 2 display connector modules available:
>>>>>> connector-analog-tv.ko, connector-hdmi.ko
>>>>>> With only the former loaded.
>>>>>>
>>>>> That is ok since the omap3 has no hdmi port.
>>>>> The panel is a separate driver.
>>>>>
>>>>>
>>>>>> menuconfig lists DPI, HDMI, SDI and DSI.
>>>>>> Is this the key here?
>>>>>>
>>>>>> And we are probably also missing the panel drivers.
>>>>>>
>>>>> Hm. The display system should work upstream - but maybe
>>>>> they are not configured?
>>>>>
>>>>> Display backlight also needs some omap pwm driver so this
>>>>> can be the reason why it does not show up in /sys/class/backlight.
>>>>>
>>>> In http://download.goldelico.com/letux-kernel/letux-4.10-rc8/src/CONFIG
>>>>
>>>> we have backlight/pwm related:
>>>>
>>>> CONFIG_BACKLIGHT_CLASS_DEVICE=y
>>>> CONFIG_BACKLIGHT_GENERIC=m
>>>>
>>> Do you know if this one is necessary? Its description is quote short.
> Unfortunately no. I would guess that CONFIG_BACKLIGHT_CLASS_DEVICE enables
> the /sys/class/backlight device.
>
>>> Just in case Debian maintainers want to know an expalantions for every
>>> option I request enabling.
>>>
>>>> CONFIG_BACKLIGHT_PWM=m
>>>> CONFIG_PWM=y
>>>> CONFIG_PWM_SYSFS=y
>>>> CONFIG_PWM_OMAP_DMTIMER=m
>>>>
>>>> And for panel:
>>>>
>>>> CONFIG_DRM_OMAP_PANEL_TPO_TD028TTEC1=m
>>>>
>>> From those, missing are:
>>> BACKLIGHT_GENERIC
>>> DRM_OMAP_PANEL_TPO_TD028TTEC1
>>> PWM_OMAP_DMTIMER
>>> I am enabling them, and rebuilding this huge allmodconfig to test later.
Turns out that the display works just fine after these changes. No
fiddling with anything in /sys.
That means backlight is on by default.
I will open a debian bug about it, hopefully they'll be as accommodating
as last time.
>> I found that replicant has
>> CONFIG_FB_OMAP2_PANEL_TPO_TD028TTEC1
> Well, there is some confusion in the display system. In fact the panel
> drivers are duplicated.
>
> Once for DRM (which I use since Debian Jessie) and the old FBDEV driver.
>
> This had some problems with X11 but might work better for FB based
> GUI systems like Replicant.
I see.
>
> BR,
> Nikolaus
>
>
>> But you don't. So I will try without it first.
>> (http://git.goldelico.com/?p=gta04-replicant-device.git;a=blob;f=rootdir/load_modules.sh;h=6ba0f4ef28af77108dff8064a5becf8f7b69d5f8;hb=refs/heads/next -  modprobe panel_tpo_td028ttec1 #Letux 2804)
>>>> BR,
>>>> Nikolaus
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