David Morgan wrote: > > Incidentally, yesterday I did some testing without any OpenGL turned > on in mythtv (v 0.20). I was capturing a show, commercial flagging > another show, watching a previous recording, *and* I had cpuburn > running. I didn't see a peep from ivtv, not one DMA error in the > half-hour I ran the test. > > Is the interaction between OpenGL/integrated video controller and ivtv > known? I haven't seen anything posted about this. Or do I possibly > have a defective piece of hardware? I'm curious to test this with a > PCIe video card (with its own memory) to see if the problem goes > away. (Not being able to use OpenGL in my setup is certainly not > tragic, but it might be nice to get workiing.) > > > On 9/19/06, *David Morgan* <[EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]>> wrote: > > > Hi, > > I've been meaning to post this. I just set up a MythTV box using > the Hauppauge 150, an ASUS A8N-VM CSM mobo, and installed with > Kubuntu Dapper 6.06 (kernel 2.6.15-26-686). I'm using the ivtv > driver 0.4.6, and added the DMA patch provided recently by Hans. > Things work pretty well, but I noticed I was getting some DMA > errors at certain times. > > I noticed once, when I happened to be watching /var/log/messages > whilst recording a show and listening to music thorugh MythMusic. > Things were bopping along fine, then I selected a visualization, > and a bunch of DMA errors showed up! The usual > > Sep 17 22:45:37 mythbox kernel: [17193111.864000] ivtv0 warning: > ENC: (0) DMA Error 0x0000000b 00000001 > > As soon as I left the visualization, the errors stopped. Next, I > selected 'blank screen', and the same errors showed up! How could > a blank screen suddenly cause trouble with DMA? Maybe there is > something going on with OpenGL... > > Well, it gave me an idea for a test. I did the following: > > 1) cat /dev/video0 > /dev/null and watch /var/log/messages > 2) Run glxgears > > Sure enough, as soon as I start glxgears, DMA errors start showing > up like crazy! As soon as I quit glxgears, the errors stop. I did > this several times (starting and stopping glxgears) whilst cat'ing > /dev/video0 to /dev/null. At one point, I started glxgears again, > and noticed that DMA errors weren't coming out. (Ok, not quite > true, there were a *few* DMA errors, but not like I saw before.) > At the same time, I noticed that in glxgears, the motion of the > gears was quite jerky, not at all like the smooth motion that I > observed in previous runs of glxgears. Not sure what to make of > that. > > Note that I am using the onboard video, a NVIDIA GeForce 6 type > controller, and that it 'borrows' main system ram for it's own use > (so that 'cat /proc/meminfo' reports 64Mb less than the 512Mb I > actually have installed. > > Oh, I also did a test where, in addition to the above, I ran > cpuburn. After a while I got the dreaded 'REG_DMAXFER 2 wait > failed' and had to reboot. > > When I get around to it, I think I'm going to purchase a PCI-E > video card and see what effect that has. I see that someone else > reported that helping... > I'm doing all of my testing with A8N-VM CSM and M2NPV-VM boards both of which have NVidia 6150 integrated graphics. I can see the problems you report, but haven't ever attributed them to running OpenGL applications. Usually it is due to having dynamic CPU throttling plus CoolNQuiet enabled whilst doing some captures. I'll have a play and see if I can simulate your problem.
Steve _______________________________________________ ivtv-devel mailing list ivtv-devel@ivtvdriver.org http://ivtvdriver.org/mailman/listinfo/ivtv-devel
