[yocto] [PATCH 2/6] crownbay: customize the xorg.conf for the flat panel on the corwnbay kit

[Darren Hart]

On 07/30/2012 02:50 AM, Kamble, Nitin A wrote:
> 
> 
>> -----Original Message----- From: Darren Hart
>> [mailto:dvhart at linux.intel.com] Sent: Saturday, July 28, 2012 3:27
>> AM To: Kamble, Nitin A Cc: yocto at yoctoproject.org;
>> bruce.ashfield at windriver.com; Zanussi, Tom Subject: Re: [yocto]
>> [PATCH 2/6] crownbay: customize the xorg.conf for the flat panel on
>> the corwnbay kit
>> 
>> 
>> 
>> On 07/26/2012 10:31 PM, Kamble, Nitin A wrote:
>>>>>> On 07/23/2012 03:06 AM, nitin.a.kamble at intel.com wrote:
>>>>>>> From: Nitin A Kamble <nitin.a.kamble at intel.com>
>>>>>>> 
>>>>>>> The kit has Auo 800x600 LCD screen. Configuring Xorg for
>>>>>>> it.
>>>>>> 
>>>>>> I presume the crownbay has additional display options? how
>>>>>> does this impact those?
>>>>>> 
>>>>> This change sets the resolution of the screen to 800x600. And
>>>>> this is applicable to LCD screen on the kit as well as
>>>>> external monitor. I will add a note about it in the log.
>>>> 
>>>> I presume that without this change it was able to detect the 
>>>> appropriate resolution of the connected monitor, but not of the
>>>> LCD?
>>>> 
>>>> If so, this change effectively breaks that autodetection and
>>>> forces everything to the 800x600 display which is arguably
>>>> very low-resolution by today's standards. Why should this be
>>>> the default? When you refer to "the kit", what exactly are you
>>>> referring to?
>>>> 
>>>> Also, is this a discussion you have already had with Tom? I
>>>> don't want to contradict what he has said regarding this BSP.
>>> 
>>> 
>>> EMGD driver on crownbay gives few resolutions as options. By
>>> default it tries to set 1366x768 resolution for both LCD and
>>> external monitor. The Crownbay kit is a suitcase kind of box,
>>> which has builtin LCD screen of resolution 800x600. This LCD
>>> screen shows only 800x600 of the default 1366x768 area. So The
>>> LCD is not able to show all the screen, and IMO it is a
>>> functional issue.
>>> 
>>> For my Dell 1704FPTi monitor which has 1280x1024 native
>>> resolution; When connected to the crownbay,  X cannot find a
>>> working mode for this monitor. But if I set 800x600 in the
>>> xorg.conf as this commit does, then both LCD & external monitor
>>> can show the X screen without any issues.
>> 
>> This seems like a bug to me. The driver should be able to probe the
>> display and use the optimal resolution without it being specified
>> in the Xorg.conf. So far as I know we don't specify resolution in
>> any of the meta-intel BSPs:
>> 
>> dvhart at envy:~/source/poky/layers/meta-intel [denzil] $ find .
>> -name xorg.conf | xargs grep -i Modes
>> 
>> So while I agree the kit screen should work out of the box, the
>> fact that even your dell lcd monitor doesn't work is cause for
>> concern. Is there anything in the Xorg log that indicates why it
>> isn't able to get the EDID data?
>> 
>> -- Darren
>> 
> 
> In the xorg log I do not see any useful EDID information. Either
> these displays do not support EDID, or the EDID support in the EMGD
> driver is not working well with these devices. And the EMGD driver is
> closed source. So we can't fix it. So IMO keeping the resolution to
> 800x600 is the best possible solution for crownbay BSP.

Tom,

I've never booted a crownbay machine. What has your experience been with
the displays on this board?

-- 
Darren Hart
Intel Open Source Technology Center
Yocto Project - Technical Lead - Linux Kernel