"Ask ATI" dev thread

[ivanovic]

One of the problems here is that a lot of the things you think of as "bugs" (eg video tearing) are actually "lack of features". Syncing video playback to vblank is one of the areas where the current X/DRI stack has always had problems (and is in the process of being re-written again), while Windows and MacOS have had a framework to support this for years.

Video tearing will be fixed by adding new features to the drivers, not by "fixing a bug" -- if it was just a question of fixing bugs we probably would have done that already.

Right, this one is a missing feature in xorg. But what about the rest. The main issues here being the OpenGL windowed/fullscreen app, known as "checkboard of hell" or "wine problem" (it happens in other apps that are not wine, too) and is a problem of the OpenGL implementation since switching to the xorg opengl implementation magically makes this problem not to appear.

Another really bad problem is the instability with xv/textured video. It must not happen that those freezes are reproducible and happening for now 4 releases already (or even more?). I think it is really bad if playing video is able to freeze all of the system and this one was already mentioned very often by now.

I think those two problems are very common and already in the driver for a long time. As such they do deserve some attention since IMO new features like overdrive and crossfire are basically worthless when the driver is not stable in "general mixed usage". IMO in this case stability is more important than new features.

In the case of textured video: yes, it is/was basically a new feature. But I expect new features to be stabilized in more recent version, not having them stay unstable.

[/rant]

I really appreciate you being here and the forums and looking at things. And I *love* the open source efforts of amd/ati which was the sole reason why I bought my hd3850. If there would not have been this effort, I would probably still be on a agp system with my good old 9800pro and (rock solid) open source drivers.

[bridgman]

I haven't looked much at either of the issues but the OpenGL windowed/fullscreen issue does sound like a regression we should have caught. We changed a lot of things in that area over the last few months in order to improve multi-head support so I'm not surprised something broke, but I am surprised we didn't catch it (I know how our QA folks love to twiddle between windowed and fullscreen until something breaks ). My guess is that the problem did not happen on our test systems, which should be a useful clue for finding and fixing it if nothing else.

I thought I saw a mention in the release notes for 8.8 that we had fixed the Xv "fail on termination" issue, at least the one we were able to repro in-house. There may be other issues which we have not been able to repro in house yet, not sure but will ask around when I get back in the office next week.

[ivanovic]

I thought I saw a mention in the release notes for 8.8 that we had fixed the Xv "fail on termination" issue, at least the one we were able to repro in-house. There may be other issues which we have not been able to repro in house yet, not sure but will ask around when I get back in the office next week.

One 100% reproducible issue I have over here with textured video (already reported it several times before):

Needed "utilities":
kaffine with xine backend and dvb support
dvb card (using a mantis based Terratec Cinergy C over here with the driver from the mantis git plus some extra patches, crashes happen without patches, too)

When setting the video backend in xine to 'Xv' (or auto, then it will be using Xv if available) and starting to view dvb the whole system will freeze with one of the typical "strange video" windows that always happen with textured video when it freezes.

To provide you with some extra data, my system specs:

Gentoo unstable based system (no matter if 32bit or 64bit)
Vanilla kernel 2.6.25.15 (older ones affected, too)
ATI HD3850 512MB
Gigabyte GA-P35-DS3
C2Q9300
4GB Ram
Kaffeine 0.8.7 (older versions like 0.8.6 affected as well)
xine-lib 1.1.14 / 1.1.15 (no idea about older, I think .13 is affected as well)

I think I saw others reporting those problems with kaffeine (xine backend) and textured video, too. When using OpenGL as render interface for xine dvb does not crash.


EDIT:
For the case it helps (I don't think so since the driver is missing the debug info), a backtrace from the crash as described above. This is the end of Xorg.log:

Backtrace:
0: X(xf86SigHandler+0x6a) [0x48dc2a]
1: /lib/libc.so.6 [0x7f91f16e32c0]
2: /lib/libc.so.6(memcpy+0xd2) [0x7f91f172fe42]
3: /usr/lib64/xorg/modules//glesx.so [0x7f91ec6697b7]
4: /usr/lib64/xorg/modules//glesx.so [0x7f91ec6c8c4f]
5: /usr/lib64/xorg/modules//glesx.so [0x7f91ec69c406]
6: /usr/lib64/xorg/modules//glesx.so [0x7f91ec69cb34]
7: /usr/lib64/xorg/modules//glesx.so [0x7f91ec61ac77]
8: /usr/lib64/xorg/modules//amdxmm.so [0x7f91ec4464e9]
9: X [0x479306]
10: /usr/lib64/xorg/modules/extensions//libextmod.so [0x7f91f0dbad5f]
11: X(Dispatch+0x340) [0x44cc30]
12: X(main+0x4a5) [0x434165]
13: /lib/libc.so.6(__libc_start_main+0xe6) [0x7f91f16cf486]
14: X(FontFileCompleteXLFD+0x281) [0x433429]

Fatal server error:
Caught signal 11.  Server aborting

[witaya]

pbo problem

In fglrx ver. 8.8's release note, they said "OpenGL PBOs no longer fail to work with GL_RGB texture format". But I still got a problem when try to update (part of) texture using glTextSubImage2D and pbo.

thanks

[Linuxhippy]

@bridgman:

Any idea when fglrx will support EXA or a custom accaleration achritecture, accalerating XRender properly?
I am currently developing a XRender based pipeline for Java, and fglrx is the only driver (intel, and now also nvidia does) which is not able to accalerate XRender.

Thank you in advance, Clemens

[wfeltmate]

Your response to my last post, Bridgeman, was actually quite enlightening and I have a much better idea of how the process works. As for the new multi-head support, I didn't even notice or know about it until after I made my post. When I saw that, I was suddenly very happy about what this new driver brought to the table. I frequently use my desktop, and now my laptop, to output movies and such to my tv over the HDMI connection, so this is a feature that I will make heavy use of. Well... once the issue with audio over hdmi is corrected haha. But, if that is the worst of my problems with fglrx, then you guys are doing a good job

[highlandsun]

Speaking of power management, I've tuned every knob possible on my new HP dv5z with HD3450 but it still runs hotter and with shorter battery life under Linux than under Windows. Since I see the CPU is idling at it's lowest power state (500MHz) I'm guessing the GPU is to blame here, and the lack of a PowerPlay-like feature on the Linux side. I would really like to be able to underclock/undervolt this GPU when the notebook is running on batteries.

[mitch074]

Update on checkerboard bug

Having installed the Catalyst 8.8 driver (doing a proper clean up before), I can now report that the mplayer -vo gl2 fullscreen/windowed switch doesn't trigger the 'checkerboard of doom' bug anymore (not even a glitch). However:
- the glitch is still present when Nexuiz 2.4.1 starts
- Wine still goes FUBAR (give me back my WoW!)
- the pattern is however less scrambled and is becoming 'predictable'.

Another bug, which must be found in the shaders code, is when using Celestia 1.5 with the OpenGL 2.0 render path: it will start by working well, but then suddenly shaded objects will get a quilted pattern of red, green, yellow, blue etc. tint. This will stay on until the driver is restarted (and X becomes unable to close normally, having to revert to a hard X Ctrl-Alt-Backspace exit ain't no idea of fun).

Last, it would be nice if texture compression could be deactivated one way or another (environment variable, control panel setting, etc.): that would help when using mplayer -vo gl2, as it currently looks washed out - but is also the only way to get vsync.

[mirv]

With the OpenGL 3.0 spec out, is that a priority now for any development? Actually any thoughts about 3.0 and ati's drivers would be interesting.

[liels]

One of the problems here is that a lot of the things you think of as "bugs" (eg video tearing) are actually "lack of features". Syncing video playback to vblank is one of the areas where the current X/DRI stack has always had problems (and is in the process of being re-written again), while Windows and MacOS have had a framework to support this for years.

Heh, I wonder how long it will take to get past the legacy of the XFree86 team. Ah well, enlightening and thanks for explainig why it's not "fixed".

I'm actually surprised that nobody is talking about the improved multi-head support we added in 8.8. That is by far the most disruptive change but it is also one of the most requested features we hear about.

Not by me. I'd rather go to a 30" screen than 2x24". My real need is for something to play nice with mythtv with a single output device.

We do understand your needs (and your frustration) and that was one of the reasons we kicked off the open source driver initiative last year. I expect that over time most consumer users will gravitate to the open source driver, since it is targeted precisely at those requirements -- simple driver, core functionality, and able to be tweaked to match your specific distribution so things like suspend/resume work reliably for relatively more users.

...

The proprietary driver will be the vehicle for delivering maximum performance and functionality, but I see it as an "upgrade path" for consumer users if they are looking for something more than the open source driver can provide.

Fair enough and we (I) appreciate the genuinely excellent steps in the right direction. What I didn't understand until recently is that the very well received 780G chipset won't work for me. I need a small quiet HTPC frontend. Something that will work with Win32 powerdvd and mythtv. For now and for the forseeable future, I can't have a HD3200 and mythtv without tearing. That's not acceptable. My temporary workaround was to throw an NVidia card into my HTPC. Mythtv now looks great and Powerdvd still works. But I've blown my heat budget and now the FE can't be both quiet and stable ...

... so I've ordered an intel G45 mobo & E8500 CPU ...

we'll see how mythdora 5 with new kernel, X.org & Mesa (or how well fedora 10 alpha does). Maybe I'll get my requirements met.

This isn't what I wanted and I'm sure AMD would rather not have other customers coming to the same conclusion.

A (likely to be hit) target date for fixing the tearing and checkerboarding problem [from ANY driver!!!] would help planning.

PS - In time I'll require p24 output on both platforms and Intel may have a problem with that (they currently do).

Thanks for the forum participation