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

[Kamble, Nitin A]

> -----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.

Nitin