Andy, I have tried the following things:
1 - I disabled Hyperthreading on my P4 3.2Ghz CPU, and for several minutes, this seemed to resolve the issue, but then it started happening again, and the picture went distorted, with lots of skipping, and jumping. MythTV would sometimes exit with "Error opening jump program file", or "Video frame buffering failed too many times". 2 - I changed grub and rebooted the machine without the GUI loaded. So this accomplished two things....no nVidia driver loaded and no Window managers running, so a fairly clean system as far as processes running. I started mythbackend, but then it exited at the end (maybe it is supposed to do that). I then started a remote frontend and the first station it tuned to gave me the same trouble. Re-started the system with graphics again. 3 - I ran the command 'v4l2-ctl --log-status' several times, but could see nothing in the output that would give me any idea of the signal quality or strength. Maybe I am not looking at the output correctly. 4 - I issued the command "modprobe ivtv debug=0x4f", but could not find any logs in the folder you specified. I did look at the output from "dmesg" and found what I believe to be the results of the debug output from the ivtv module. However, there is only so much space, it seems, in the output from dmesg, and I could not find anything that was there that would give me a clue as to what is going on. Is there a way to get the debug mode for the ivtv module to redirect its output to a log file, so I can comb through it without worrying about the buffer space in dmesg? 5 - I looked to see if I could load IRQbalance as you suggested, and found that it was already running under Mythbuntu 11.04. I then unloaded it, rebooted and tried again - no difference. I tried ftrace, but I believe it is beyond my abilities to configure and run at the moment. I do not know how to mount the debug file system or enable the option on the Ubuntu kernel. I have seen the MythTV bug reports, but they do not seem to apply exactly to my situation, however, I cannot help but think that they are at least linked to what is going on with my system. I do not believe it is a latency issue, as adjusting the latency of the cards and other things on my system made no difference in the behavior of the analog tuner (PVR-150's) at all. I also do not think it has anything to do with changing channels, as I have had distorted video come up when first bring up my frontend...any frontend. I know I should not let this get to me, but I had a working system under Mythbuntu 8.10, and it doesn't work under 11.04. I found that the issue actually began, or has something to do with the changes between Mythbuntu 8.10 and 9.10. I don't know where the changes are located that would affect analog tuners, but I will guarantee you the source of the issue is there. The problem still existed in Mythbuntu 10.10, as well. Perhaps someone that is familiar with the design architectures of Linux and Mythbuntu could point us all in the right direction. Andy, I want to thank you for your help so far. I would not have gotten this far without your help. Thanks for taking pity on an aging engineer. -----Original Message----- From: Andy Walls [mailto:[email protected]] Sent: Saturday, January 28, 2012 8:25 AM To: [email protected] Cc: [email protected] Subject: Re: [ivtv-users] Help With Troubleshooting On Thu, 2012-01-26 at 18:39 -0600, [email protected] wrote: > ==============Original message text=============== On Wed, 25 Jan 2012 > 9:40:11 pm CST Andy Walls wrote: > [email protected] wrote: > >>Hello, > >>I have two servers running Mythbuntu 11.04 and MythTV 0.24.1. > >>I have > >>three PVR-150 tuners in the server configured as a slave backend, > >>and some digital tuners in the master backend. The problem I have > >>is that whenever the analog tuners are called for by any frontend > >>(even a local one), I get distorted video, with stuttering and image > >>freezes. There is currently a bug report in with MythTV on a > >> Analog Channel Change issue. > >>I have tried the work-a-round (tune a digital channel before using > >>one of the analog tuners), but it does not work for me. I finally > >>saw some troubleshooting steps for IVTV drivers, and followed some > >>of those steps. > >>The one that caught my attention, is the cat /dev/video1 > > >>test.mpg test. I looked at the file that was produced while the > >>command was active, and VLC would only play a few seconds of the > >>file and then skip to the end, and then terminate the viewing > >>window. The video jumped and was distorted, just the same as it was > >>in MythTV. So the issue, evidently, is not MythTV, but perhaps with > >>IVTV or some related item. > >>On a related note, the same hardware works without issues, when > >>running MythTV 0.21 under Mythbuntu 8.10. > >>What would you do next and where would you look for a>>resolution? > >>Thanks, > >>Jeff > >What are the kernel versions shown with uname -a? > Linux MYTHBE2 2.6.38-13-generic #54-Ubuntu SMP Tue Jan 3 13:44:52 UTC > 2012 i686 i686 i386 GNU/Linux OK, fairly modern; that's good. Do you happen to know the kernel version under Mythbuntu 8.10? (so I check the differences between the two kernels) > >What are the ivtv-driver versions shown with v4l2-ctl -d /dev/video1 > >--log-status? > ivtv1: Version: 1.4.2 Card: Hauppauge WinTV PVR-150 OK, good. > >What other devices are shown sharing the interrupt lines with ivtv > >using cat /proc/interrupts? > CPU0 CPU1 > 0: 580 0 IO-APIC-edge timer > 1: 3649 0 IO-APIC-edge i8042 > 6: 3 0 IO-APIC-edge floppy > 7: 0 0 IO-APIC-edge parport0 > 8: 1 0 IO-APIC-edge rtc0 > 9: 0 0 IO-APIC-fasteoi acpi > 14: 63335 0 IO-APIC-edge ata_piix > 15: 1294927 0 IO-APIC-edge ata_piix > 16: 7153671 2827260 IO-APIC-fasteoi uhci_hcd:usb2, uhci_hcd:usb5, > nvidia > 17: 12238 7179 IO-APIC-fasteoi ivtv1 > 18: 5690498 0 IO-APIC-fasteoi ata_piix, uhci_hcd:usb4,eth0, > Ensoniq AudioPCI > 19: 74042 0 IO-APIC-fasteoi uhci_hcd:usb3, ivtv2 > 22: 1829 0 IO-APIC-fasteoi ivtv0 > 23: 3 0 IO-APIC-fasteoi ehci_hcd:usb1 > NMI: 0 0 Non-maskable interrupts > LOC: 14667959 15620982 Local timer interrupts > SPU: 0 0 Spurious interrupts > PMI: 0 0 Performance monitoring interrupts > IWI: 0 0 IRQ work interrupts > RES: 2407721 2344290 Rescheduling interrupts > CAL: 789 2664 Function call interrupts > TLB: 13663 20105 TLB shootdowns > TRM: 0 0 Thermal event interrupts > THR: 0 0 Threshold APIC interrupts > MCE: 0 0 Machine check exceptions > MCP: 540 540 Machine check polls > ERR: 0 > MIS: 0 This looks pretty imbalanced: CPU0 handles a lot more of the interrupt service than CPU1. This imbalance of CPU0 handling most of the hardware interrupts might be a source of problems, *if* CPU0 is actually busy with higher priority interrupts (ata_piix, nvidia) when the ivtv* card interrupts come in. The disk drive (ata_piix) and network card (eth0) interrupts have only been handled by CPU0. Is "irqbalance" running on your system? For a back end system, I have to wonder what the nvidia card is doing for you, assuming it it the only device generating interrupts on IRQ16. It has genearted 9.98M interrupts in the same time of 30.3M local timer interrupts (1 nvidia card interrupt per every 3 timer interrupts). > Looks like one of the USB ports shares its IRQ with one of the cards, > but my issue happens with all three cards, so that doesn't seem to be > the likely cause of the issue. Right, especially if there are no USB devices connected to the port that IRQ19 serves. > >What is the cpu loading shown with top during video capture? Are > >there high numbers for user or io wait percentages? > Tasks: 146 total, 1 running, 145 sleeping, 0 stopped, 0 zombie > Cpu(s): 7.2%us, 4.0%sy, 0.0%ni, 88.8%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st > Mem: 2059632k total, 1143540k used, 916092k free, 112388k buffers > Swap: 2095100k total, 0k used, 2095100k free, 688688k cached > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > 2799 jpreston 20 0 214m 49m 24m S 2 2.5 36:37.44 knotify4 > 7959 jpreston 20 0 72220 12m 9.8m S 2 0.6 0:04.54 xfce4-terminal > > 1263 root 20 0 88408 51m 14m S 1 2.6 1:35.49 Xorg > 8028 jpreston 20 0 3360 504 440 S 1 0.0 0:00.35 cat > 8082 jpreston 20 0 2632 1136 848 R 1 0.1 0:00.08 top > 1345 jpreston 20 0 6464 2516 1788 S 0 0.1 0:06.88 xscreensaver > 1 root 20 0 3028 1792 1216 S 0 0.1 0:00.90 init > 2 root 20 0 0 0 0 S 0 0.0 0:00.04 kthreadd > 3 root 20 0 0 0 0 S 0 0.0 0:01.95 ksoftirqd/0 > 5 root 20 0 0 0 0 S 0 0.0 0:03.60 kworker/u:0 > 6 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/0 > 7 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/1 > 9 root 20 0 0 0 0 S 0 0.0 0:00.71 ksoftirqd/1 > 11 root 0 -20 0 0 0 S 0 0.0 0:00.00 cpuset > 12 root 0 -20 0 0 0 S 0 0.0 0:00.00 khelper > 13 root 0 -20 0 0 0 S 0 0.0 0:00.00 netns > 15 root 20 0 0 0 0 S 0 0.0 0:00.27 sync_supers > This was captured during a cat /dev/video1 > test.mpg, and the CPU > usage never went above a few percent for any process. The file was > still distorted and flawed. OK. Plenty of memory (894 MB RAM still free), plenty of CPU (88.8% idle), nothing waiting on I/O (0.0% wa). 'cat' consuming only 1% of CPU may be a little low, since the ivtv driver and cat collectively do some buffer copies in the read() call that cat makes into the ivtv driver. (May indicate not many filled video buffers being provided by the ivtv driver). Given this, the best guesses I have are: 1. an interrupt handling latency problem. 2. a PCI bus/chipset problem: DMA transfers aborting or IO transactions to registers and memory on the CX23416 chip are being aborted 3. an ivtv driver bug/race in setting up the CX23416 decoder, that causes problems in the decoder actually running 4. a cx25840 driver bug in setting up the CX25843 chip to lock on to the video signal and digitize it properly 5. an analog tuner driver bug that causes tuning to fail > Where else can I look for this? Do you have any other ideas? For #4 and #5 above, the output of several runs of 'v4l2-ctl --log-status' should let you know if the CX25843 has a good video signal. For #2 and #3, setting the debug=... option to the ivtv driver in /etc/modprobe.conf or on the modprobe ivtv command line will turn on various levels of logging in the ivtv driver (with messages emitted to /var/log/messages normally). $ modinfo ivtv [...] parm: debug:Debug level (bitmask). Default: 0 1/0x0001: warning 2/0x0002: info 4/0x0004: mailbox 8/0x0008: ioctl 16/0x0010: file 32/0x0020: dma 64/0x0040: irq 128/0x0080: decoder 256/0x0100: yuv 512/0x0200: i2c 1024/0x0400: high volume [...] So maybe, as root, # modprobe -r ivtv # modprobe ivtv debug=0x4f (or =0x44f) And then do a 'cat /dev/videoN > foo.mpg' and examine all the debug spew in /var/log/messages to see what is wrong. For #1, I'd experiment with how does video capture behave with a. having irqbalance running (or not running) b. booting into only run-level 3 (text console, no GUI/X) and unloading the nvidia driver module I would also look at IRQ handling latency with ftrace and other kernel tracing mechanisms: http://lwn.net/Articles/322666/ http://lwn.net/Articles/322731/ http://lwn.net/Articles/366796/ http://lwn.net/Articles/365835/ http://www.spinics.net/lists/linux-media/msg15762.html Regards, Andy > Thank you much for your assistance so far. > Jeff > ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.1901 / Virus Database: 2109/4772 - Release Date: 01/28/12 _______________________________________________ ivtv-users mailing list [email protected] http://ivtvdriver.org/mailman/listinfo/ivtv-users
