Bug 24462
| Summary: | RFE: Auto calculate optimal modelines if possible. | ||
|---|---|---|---|
| Product: | [Retired] Red Hat Linux | Reporter: | Need Real Name <mal> |
| Component: | XFree86 | Assignee: | Mike A. Harris <mharris> |
| Status: | CLOSED NOTABUG | QA Contact: | David Lawrence <dkl> |
| Severity: | medium | Docs Contact: | |
| Priority: | low | ||
| Version: | 7.0 | Keywords: | FutureFeature |
| Target Milestone: | --- | ||
| Target Release: | --- | ||
| Hardware: | i386 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Enhancement | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2003-04-25 10:05:24 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
above I mant 1024x768 non-interlaced. i before the mode is a misprint I'd say generating Modelines is Xconfigurator's job rather than XFree86's... Re-working Xconfigurator to provide absolutely "optimal" refresh rates is going to be very difficult. Remember that this tool needs to run on the widest array of hardware available. 85 Hz is higher than most humans can detect as a refresh rate. Yes, 100 Hz is better. This kind of fixup will have to remain in the domain of manual tweaking for now. This should not be really hard. You can extract all supported clock frequencies from the videocard (X server just prints them to stderr) You know a resolution (it 3 or 4 four possible options 640x480, 800x600, etc.) then knowing clock frequency and resolution you should be able to calculate all timing options in Modeline. The problem with current /etc/X11/XF86Config ih has pre-set DotCloc like in the line below DotClock is 69.65 Modeline "800x600" 69.65 800 864 928 1088 600 604 610 640 -HSync -VSync The problem if the videocard supports DotClock 75.0 this mode will not work. So the right approach is to take DotClock from videocard and generate the all modes supporthing this DotClock. Totally you you get the most N_DotClock_modes * N_different_resolutions. In effect this number is 2-3 times fewer because some combinations are not possible because of limited videoram. You will end up with about the same number of modes as you have now in XF86Config but all of them will be supported. Below are the links with the information how using DotClock and resolution calculate timing. This way Xconfigurator can set the best modes which will perfectly fit the videocard. http://florida.linuxusers.org/howto/hi-res/ http://www.kernelnotes.org/HOWTO/XFree86-Video-Timings-HOWTO-10.html http://www.icewalk.com/softlib/app/app_00902.html I think the best option is to put all N_DotClock_modes * N_different_resolutions. possible Modeline and let the server itself to select those which will work with availble videoram. The first link http://florida.linuxusers.org/howto/hi-res/ has the most clear description. The other focus on some very special things (like non-standrad screen resolution and etc.) *** Bug 24704 has been marked as a duplicate of this bug. *** If there are modelines missing, they should be added directly to XFree86 itself. XFree86 uses whatever modelines it has built in, and any specified in the config file. If there are modes you'd like added, feel free to attach the modeline to the bug report and reopen the bug. I meant that there is an easy way to create perfect modelaine options for every videocard. https://bugzilla.redhat.com/bugzilla/showattachment.cgi?attach_id=9199 By extracting dot-frequencies from videocard (X server just prints them to console) and knowing the display resolutions 1024x768, 800x600, etc one can just generate perfect modelines for the specific videocard. This was the whole point. Not to chose some pre-selected modelines, but instead generate them based on available videocard and required display resolution(s). See the link above for a very simple algorithm for this task. Ok, I gotcha. I'll check it out for future releases. Thanks. This is development which should be done by XFree86.org and integrated into a future release of XFree86 upstream. It is something they've discussed doing, and so I'm closing this bug out since it is something that will be done upstream and not by Red Hat. |
The X11 (XFree86-4.0.1-1) Often does not select the best mode. An example: when setting in /etc/X11/XF86Config-4 Modes "1024x768" The mode 1024x768 was set at 85Hz, but the monitor perfectly supports i1024x768 at 100Hz. To get it to work at 100Hz I needed to put a "Modeline" line to Monitor section (copied from /etc/X11/XF86Config) After that it started working OK at 1024x768 @100Hz. I think XFree86-4 should itself select the best available frequenciy.