[PATCH V6 0/8] drm/exynos: few patches to enhance bridge chip support

[Ajay kumar]

On Thu, Jul 31, 2014 at 2:27 PM, Andreas Färber <afaerber at suse.de> wrote:
> Ajay,
>
> Am 31.07.2014 10:38, schrieb Ajay kumar:
>> On Thu, Jul 31, 2014 at 1:02 AM, Andreas Färber <afaerber at suse.de> wrote:
>>> Am 30.07.2014 08:21, schrieb Ajay kumar:
>>>> On Tue, Jul 29, 2014 at 4:51 PM, Andreas Färber <afaerber at suse.de> wrote:
>>>>> Am 28.07.2014 08:13, schrieb Ajay kumar:
>>>>>> On 7/27/14, Andreas Färber <afaerber at suse.de> wrote:
>>>>>>> Am 25.07.2014 21:22, schrieb Ajay Kumar:
>>>>>>>> This series is based on exynos-drm-next branch of Inki Dae's tree at:
>>>>>>>> git://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos.git
>>>>>>>>
>>>>>>>> I have tested this after adding few DT changes for exynos5250-snow,
>>>>>>>> exynos5420-peach-pit and exynos5800-peach-pi boards.
>>>>>>>
>>>>>>> I'm trying to test this with a modified exynos5250-spring DT based off
>>>>>>> kgene's for-next branch due to DT, and I run into the following:
>>>>>
>>>>> Unfortunately the most I got on Spring with attached DT was a blank
>>>>> screen with a white horizontal line in the middle.
>>>> Then, I think bridge chip is working fine.
>>>> You just need to configure the proper mode for FIMD.
>>>> You can see backlight also, right?
>>>>
>>>>> Do I need to specify a specific panel model for Spring?
>>>> Yes! Try using "chunghwa,claa101wb01" as compatible string for
>>>> panel node.
>>>
>>> With just your v6 applied plus updated DT patch (attached) [1], I see
>>> backlight and a black screen (no white line any more). dmesg attached.
>> I can see penguin's also!
>
> See below...
>
>>>>> For testing I re-applied your iommu patches (which btw fail now for 5420
>>>>> due to disp_pd) but didn't know what to do about your panel-lvds
>>>>> regulator patch now that it's gone.
>>>> Ignore that regulator patch.
>>>>
>>>> Also, please attach the bootlog if possible after trying this.
>>>
>>> If I further apply the IOMMU patches [2], I get no backlight nor USB and
>>> thus can't obtain a boot log.
>>>
>>> Regards,
>>> Andreas
>>>
>>> [1] https://github.com/afaerber/linux/commits/spring-next
>
> (I updated the branch meantime, so what I meant was spring-bridge.v6~2)
>
>>> [2] https://github.com/afaerber/linux/commits/spring-bridge.v6
>> With just the spring-bridge.v6 branch of your own tree, I am able to see
>> bootup logo on Skate(a variant of spring which also contains ps8622).
>> I have tried both exynos_defconfig and multi_v7_defconfig.
>> I enable DRM, EXYNOS DRM, BRIDGE CHIPS, IOMMU, EXYNOS IOMMU
>> in configs.
>>
>> Even in your bootlogs, I can see DP getting probed.
>> And, you say backlight is also visible. That means entire display
>> path should be fine. Its just that you should start writing to the buffer.
>> Have you enabled boot logos?
>
> Let me clarify: U-Boot uses the display [*], so it is powered and I see
> penguins initially. Then, when drm gets initialized, the screen goes
> black and no longer prints kernel messages or systemd output or X11 gdm
> login screen.
>
> Since drm stuff is the only variance here and it works with simplefb,
> surely something prints to some buffer!
Well, I cannot really help you with this.
I think the ui process/X server is getting terminated for some reason.
That might be some issue induced by the platform/drm lib.
This cannot be an issue induced by the bridge chip series, definitely not!
I am able to run modetest, and also able to see random data on display
by doing "cat /dev/urandom > /dev/fb0"

Ajay