1 2If the box freezes hard with bttv ... 3===================================== 4 5It might be a bttv driver bug. It also might be bad hardware. It also 6might be something else ... 7 8Just mailing me "bttv freezes" isn't going to help much. This README 9has a few hints how you can help to pin down the problem. 10 11 12bttv bugs 13--------- 14 15If some version works and another doesn't it is likely to be a driver 16bug. It is very helpful if you can tell where exactly it broke 17(i.e. the last working and the first broken version). 18 19With a hard freeze you probably doesn't find anything in the logfiles. 20The only way to capture any kernel messages is to hook up a serial 21console and let some terminal application log the messages. /me uses 22screen. See Documentation/serial-console.txt for details on setting 23up a serial console. 24 25Read Documentation/oops-tracing.txt to learn how to get any useful 26information out of a register+stack dump printed by the kernel on 27protection faults (so-called "kernel oops"). 28 29If you run into some kind of deadlock, you can try to dump a call trace 30for each process using sysrq-t (see Documentation/sysrq.txt). 31This way it is possible to figure where *exactly* some process in "D" 32state is stuck. 33 34I've seen reports that bttv 0.7.x crashes whereas 0.8.x works rock solid 35for some people. Thus probably a small buglet left somewhere in bttv 360.7.x. I have no idea where exactly, it works stable for me and a lot of 37other people. But in case you have problems with the 0.7.x versions you 38can give 0.8.x a try ... 39 40 41hardware bugs 42------------- 43 44Some hardware can't deal with PCI-PCI transfers (i.e. grabber => vga). 45Sometimes problems show up with bttv just because of the high load on 46the PCI bus. The bt848/878 chips have a few workarounds for known 47incompatibilities, see README.quirks. 48 49Some folks report that increasing the pci latency helps too, 50althrought I'm not sure whenever this really fixes the problems or 51only makes it less likely to happen. Both bttv and btaudio have a 52insmod option to set the PCI latency of the device. 53 54Some mainboard have problems to deal correctly with multiple devices 55doing DMA at the same time. bttv + ide seems to cause this sometimes, 56if this is the case you likely see freezes only with video and hard disk 57access at the same time. Updating the IDE driver to get the latest and 58greatest workarounds for hardware bugs might fix these problems. 59 60 61other 62----- 63 64If you use some binary-only yunk (like nvidia module) try to reproduce 65the problem without. 66 67IRQ sharing is known to cause problems in some cases. It works just 68fine in theory and many configurations. Neverless it might be worth a 69try to shuffle around the PCI cards to give bttv another IRQ or make 70it share the IRQ with some other piece of hardware. IRQ sharing with 71VGA cards seems to cause trouble sometimes. I've also seen funny 72effects with bttv sharing the IRQ with the ACPI bridge (and 73apci-enabled kernel). 74 75