Linux HOW-TO setup XBMC and Linux with correct resolution (xorg.conf)

It depends on the source material. If your source material is 24p (ie 24Hz, it will look worse in 50Hz then in 24Hz). If you use this guide to setup up correct refresh rates XBMC will automatically switch to the source materials refresh rate.

biggles Wrote:Use it as an addition to the other options.

Sorry but it's still unclear. When should I add it? Before I run the X test or after?

But it might be unnecessary. I took your advice and started reading on the xorg.conf file and when I got to the ExactModeTimingsDVI option, I discovered that setting it to True tells X to read the timing info from the xconf.org instead of the EDID (or so i gather). I've set it to True after reading in this forum about a few xorg.conf setting that should help raising the framerate and indeed those settings raised my framerate from 17FPS to 24FPS, but apparently the ExactModeTimingsDVI was unnecessary. I removed it yesterday and so far had not seen the problem return while the framerate remains at about 24FPS.

EDIT: I replaced my old config file i posted here because it gave trouble with the audio output (sound cuts), so i assume that the horiz/vertrefresh didnt work properly. i created this new config file with the help of the native nvidia settings tool + saved it with it.

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After trying around for about a week with my new toshiba 42" full hd 24p LCD i finally found a xorg.conf that works without stutter or skipping.

Set xbmc to automaticly set the refresh rate

this xorg.conf was tested on an e8400 / 2 gb / geforce 9400gt setup

In the process of tweaking mine, haven't had a chance to test. Just something to note regarding the posted EDID options. According to NVIDIA's website:

Quote:Option "UseEDID" "boolean"

By default, the NVIDIA X driver makes use of a display device's EDID, when available, during construction of its mode pool. The EDID is used as a source for possible modes, for valid frequency ranges, and for collecting data on the physical dimensions of the display device for computing the DPI (see Appendix W, Dots Per Inch). However, if you wish to disable the driver's use of the EDID, you can set this option to False:

Option "UseEDID" "FALSE"

Note that, rather than globally disable all uses of the EDID, you can individually disable each particular use of the EDID; e.g.,

Option "UseEDIDFreqs" "FALSE"
Option "UseEDIDDpi" "FALSE"
Option "ModeValidation" "NoEdidModes"

Default: True (use EDID).

I will try disabling all first and report back later with the results:

A previous post also noted several EDID rejected modes. The NVIDIA forum link seems to indicate that was cleared by specifying the modes and ignoring the EDID as we are doing here. I show the same in my Xorg logs. So the assumption is these may be gone if we just use:

AmirG Wrote:I took your advice and started reading on the xorg.conf file and when I got to the ExactModeTimingsDVI option, I discovered that setting it to True tells X to read the timing info from the xconf.org instead of the EDID (or so i gather). I've set it to True after reading in this forum about a few xorg.conf setting that should help raising the framerate and indeed those settings raised my framerate from 17FPS to 24FPS, but apparently the ExactModeTimingsDVI was unnecessary. I removed it yesterday and so far had not seen the problem return while the framerate remains at about 24FPS.

Oh damn. Seems like everytime I manage to fix a problem, I discover it hid another problem behind it.

The ExactModeTimingsDVI=True was not the (only) cause of my problem, removing it only made it less frequent.

So I tried again and this time, all the relevant modes were valid! Why? Not sure. It could be the absence of the ExactModeTimingsDVI otr the fact that this time, I ran X directly from the console and not through SSH. But guess what - a new problem just poped it's ugly head.

I've got three valid 1080p modes: 60Hz, 50Hz and 24Hz but onlt two 720p modes: 60Hz and 50Hz, no 24Hz. It wasn't even tested. Now almost all HD content I watch is 720p (XBMC 9.04 can't handle 1080p on my setup, hopefully the next stable version will). The debug display shows the framerate at 24FPS (with minor fluctuations), I have no idea how to tell the mode the TV is running at - it's 720p, but I have no idea what the refreshrate is. But if it's 50Hz or 60Hz instead of 24Hz, that would explain the tearing I get whenever the camera panes: The HTPC and the TV refreshrates are out of sync.

Anything I can do to fix that?

I have an issue with setting up my xorg.conf correct. I am a Linux (command line) noob, but I would like to run xbmc live on an usb stick on my laptop, with my tv connected via VGA. In windows, xbmc for windows works perfect, but I would like to run xbmc live on an usb stick. I can't get a signal to my tv in Linux.

laptop: compal ifl90
TV panasonic px80
connection: VGA cable

How should I set up xorg.conf to get a signal to my tv, or should I start more basic with activating my VGA port (not sure if xorg.conf does this). When I browse through my xorg.conf I can only see one display (laptop display).

thanks.

I looked at the Xorg.0.log, Ubuntu starts at 1080p 50Hz and XBMC switches to 720p 60Hz. Thought I'll try 1080p 24Hz, which is a valid mode I've defined a modeline for, but there's no such mode in XBMC. When I looked at the xorg log again, I saw something I've missed the 1st time:

Huh? How can the screen support 24Hz mode if the lowest valid refresh rate is 48Hz? I thought it might be doubling the input resolution, until:

So it's a valid mode but the screen claims it can't handle the refresh rate and therefore X won't use it.

Is it safe to try and set the VertRefresh at 24 even though the screen insists it can't go lower then 48Hz?

Oh, and I still lose the picture and voice for a few seconds on occasion.

Edit:

OK, seems like it's solved. I've set the min VertRefresh to 24 (while praying to all major gods it won't damage my TV) and added the "UseEDIDFreqs" "FALSE" option and now the 1080p24 mode appears as valid and XBMC lets me choose it. It seems like there's no tearing in that mode, however I'm only getting about 17FPS. I gather the new stable version, due by the end of the month, will greatly boost the performance, hopefully it'll enable me to use this mode.

Thanks for the help!

Hi,

I have a Pioneer Kuro PDP-C509A TV which supports 1920x1080@24, 1920x1080@50 and 1920x1080@60 when connected via HDMI (which it is), however when I follow the instructions in this thread I get the following output in my log file:

http://files.me.com/m.dobrzynski/v8kztu

I'm stuck. Any tips on what I should do?

Regards,
Michal

Chambers Wrote:Does this fix the problem if the Ubuntu desktop goes off the screen? What I mean is that that top and bottom bars aren't visible because the system thinks my viewing area is larger than what it is. I basically have to take my mouse and move it up and guess where the menu is (for gnome). Just wondering it this will fix that?

Hi,

I have the same problem as Chambers. Any ideas?

/Per

I have to ask. Why are we using Option "ModeValidation" "NoEdidModes" ??

Isn't this what is causing:

Mode is rejected: Modes from the PIONEER_TV (DFP-1)'s EDID are not allowed.

for ALL the supported HDTV modes of my TV? How can it ever be valid as described in the original post if we're excluding all EDID modes in the config? Or is this only for TV's with broken EDID's? Seems counter intuitive.

Should I be safe in creating modelines from the entries reported by the EDID? If I just let X use the modelines it detects I do not get 1920x1080@24 or @60 options in XBMC.

Regards,
Michal