> or blows up a TV

Wait you can blow up a Flat Panel TV when the Signal is out of spec?
I could think of this with a CRT but not really with an TFT or Plasma which all have digital preprocessing which either works, or does not work.


@Marq:

You could compile your own Kernel and try hacking in the Numbers in the Code there or pass these through U-Boot parameters ;)

I cannot believe that you cannot get ANY video mode working on my Sony TV. I even tried disabling 1080 and manually setting a mode, but no cigar. What sense does it make to override manual settings by non-working autodetect modes? It's not a hardware limitation beyond help, because the Android demo works.

How about first using some safe working default and then letting the user select another? If the user doesn't confirm it's working within, say, 10 seconds, restore the previous mode? That of course requires the existence of a "safe working default" mode.

All in all I don't get the need to stick to the initial video mode only. On most desktop Linux platforms you can set a mode in X11 anytime and even add new modes on the fly with xrandr.

That requires some coordination between a simple framebuffer driver and X11 driver that simply does not exist right now. "On most desktop Linux platforms" they are using DRM Connectors, KMS and GEM and so on which allows this coordination to happen as a matter of architecture.

_________________
Matt Sealey

Let's put it this way: if we didn't follow the spec and just let you set the mode, you would get far more black screens on far more monitors. Manually setting the mode you want (video=1280x720@60) is not guaranteed to pick the correct mode any more than the current mode. Manually picking an incompatible mode will give you a black screen. You are at the mercy of the EDID. This isn't a CRT monitor where you can tweak the modes ever so slightly and still have them always work. LCDs just aren't that flexible.

The problem with your Sony - and a couple other monitors we have to test - is that they report they CAN display the mode it picks, when in actual fact they simply cannot.

This is a bug in your monitor. Unfortunately the only way around it is to detect your monitor and do something different, but imagine doing this for every monitor on the planet to find the perfect mode.

The difference is, Android *forces* 720p@60. We gracefully detect 720p@XX. Your TV says it can do 720p@50 and 720p@60 and the automatic mode detection picks the 50Hz mode. And your TV responds by giving you a black screen.
The solution we're working on right now will basically change the behavior of the mode culling, since in most of the cases of black monitors, it is because we take out all duplicate PC modes where there is a CEA analog (therefore if the monitor says it can do "1280x720@60" and "CEA Mode 4", we remove the 1280x720 mode since CEA mode 4 is the same thing).

Some HDMI TVs will overscan CEA modes regardless. We want to avert this by keeping the PC mode in there instead. For HDMI TVs connected via DVI or DVI monitors, we definitely want to keep the PC mode.

And for modes where two exist with different refreshes we will let you pick if you want to use one or the other, but it's kind of difficult to work out a heuristic to detect this: we know you have two modes in the EDID with similar refresh, however we cannot know which one does not work, the order in the EDID may change monitor to monitor (or be an IT mode vs. a CEA mode as above).. it's a complicated thing to work out.

Not even the AMD Catalyst drivers on the PC do it correctly as I have seen on my TV at home.

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Matt Sealey

Okay I hammered out the changes today and committed them to the kernel repository.

If anyone wants to test this kernel please bug me at matt at genesi-usa.com so I can mail you the .deb and an update to flash-kernel.

There are some switches you need to set to make the behavior on your monitor change which might imply that you need some kind of working display in the first place. What we have tested so far is that even with the changes to the parser, all the monitors here work the same (i.e. nothing breaks that wasn't already broken by default).

The changelog:

https://gitorious.org/efikamx/linux-ker ... d7a95aa403

There may be outliers which we cannot test whereby DVI monitors stop working because of the modification to the lower_margin check. As far as I see, it works for all our test monitors, but this is technically a regression to an older behavior which made a lot of peoples' DVI monitors come up with sync errors.

The change that might make the Sony monitor (above) work is that the default mode is now 1280x720@60 so if any fallback is performed, it will be the same as the Android mode. If the monitor still doesn't work, we will know that it is not the fallback mode that doesn't work! Note that if anyone is in Europe with a TV that only does 720p@50Hz for some reason (this should be kind of rare) and the fallback has to happen, then their TVs will break now. I don't think we can really solve this. We picked the 50Hz mode because it was the one we'd gracefully detect and couldn't find a monitor that said it couldn't do it.

(as an aside, the "Setting resolution: 1280x720@512" output is fixed, it will display a much more relevant number)

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Matt Sealey

If it would help my HDMI output to get to 1366x768, I'll give it a try. With the exception of that, I've really enjoyed this little computer. Do you need an e-mail address, or can you get it from out here?

Kernel and kernel option below works on the Panasonic TX-P42G20B in 720P.

siihdmi.force_dvi=1

http://www.powerdeveloper.org/linux-ima ... _armel.deb

Superb support Neko.

How or where do I pass the "siihdmi.force_dvi=1" to the kernel? I knew how to do that with GRUB, but not with u-boot. I plan to try it tonight when I get home. Will let you know my outcome. Thanks...

I installed the new kernel, but I'm still getting 1280x720. I did notice this time when I ran xrandr -q, it did show the 1360x768, but I couldn't change to it. I think I'm still missing how and where to pass "siihdmi.force_dvi=1" to the kernel. any help with this?

you will need to modify the boot.scr file; this file is re-written whenever you install a new kernel, so the best thing to do is to create your own copy of it.

I like to make a boot.scr.steev, and then modify it as needed.

Remove the beginning of the first line, which is the script's encoding, as we will be re-encoding it after modifying it, so the first line should look something like

setenv ramdisk uInitrd-2.6.31.14.23-efikamx;

and then on the bootargs line, before the ';' you will want to add any options you want to pass, and then save the file.

then you just run the command

mkimage -A arm -T script -C none -n "EfikaMX boot script" -d boot.scr.steev boot.scr

(in /boot)

And then reboot. When playing around with the boot.scr file, you WILL want to have an sd card with the installer image on it handy so that you can boot the EfikaMX with it if you happen to make a mistake.

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Steev Klimaszewski, Genesi USA Inc.
Senior Software Engineer

Well I did have some success. The display is still defaulting to 1280x720, but it fits in the screen now. This is definitely a big help. I'm sure eventually it will use the 1360x768, but as long as I can see everything on the screen and nothing is cut out, I'm happy. Thanks to both of you for your assistance on this.

Good to hear that you got it sort of working.

I think the reason you can't use xrandr is because there is no support for it in the Efika MX's Xorg driver. As far as I have understood, the xrandr command-line program is simply a front-end program for tapping into the Xorg driver's implementation of "The X Resize, Rotate and Reflect Extension" (RandR extension).
The RandR extension is basically what lets a computer program dynamically change the resolution of a screen without restarting X.
http://en.wikipedia.org/wiki/Xrandr

Have you tried editing your xorg.conf though (usually in /etc/X11/xorg.conf)?

You could try, after first backing up the existing xorg.conf, to put the following in /etc/X11/xorg.conf
then restarting the system while your TV is plugged in and turned on.

I tried to create an xorg.conf file using Xorg -configure, but it fails. I had thought about that too. I created one with just the lines above, but there is no change. I'm sure I need other information in my xorg.conf file besides that. I'll keep trying, but at least I don't have to have extra toolbars around the screen now to push everything in view. I'm really amazed at how well this thing works. Thanks again.

Could you post your /var/log/Xorg.0.log file after starting the system with the xorg.conf from my previous post?
Xorg should be saying something about why it doesn't choose the resolution we have set in xorg.conf.

Also, could you try this xorg.conf to see if it works:
using "1360x768@60" to describe the mode, which is what is in your previously posted Xorg log here: http://www.powerdeveloper.org/forums/vi ... 1854#14772