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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/video4linux/bttv/README.freeze | |
download | linux-3.10-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz linux-3.10-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.bz2 linux-3.10-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'Documentation/video4linux/bttv/README.freeze')
-rw-r--r-- | Documentation/video4linux/bttv/README.freeze | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/Documentation/video4linux/bttv/README.freeze b/Documentation/video4linux/bttv/README.freeze new file mode 100644 index 00000000000..51f8d4379a9 --- /dev/null +++ b/Documentation/video4linux/bttv/README.freeze @@ -0,0 +1,74 @@ + +If the box freezes hard with bttv ... +===================================== + +It might be a bttv driver bug. It also might be bad hardware. It also +might be something else ... + +Just mailing me "bttv freezes" isn't going to help much. This README +has a few hints how you can help to pin down the problem. + + +bttv bugs +--------- + +If some version works and another doesn't it is likely to be a driver +bug. It is very helpful if you can tell where exactly it broke +(i.e. the last working and the first broken version). + +With a hard freeze you probably doesn't find anything in the logfiles. +The only way to capture any kernel messages is to hook up a serial +console and let some terminal application log the messages. /me uses +screen. See Documentation/serial-console.txt for details on setting +up a serial console. + +Read Documentation/oops-tracing.txt to learn how to get any useful +information out of a register+stack dump printed by the kernel on +protection faults (so-called "kernel oops"). + +If you run into some kind of deadlock, you can try to dump a call trace +for each process using sysrq-t (see Documentation/sysrq.txt). ksymoops +will translate these dumps into kernel symbols too. This way it is +possible to figure where *exactly* some process in "D" state is stuck. + +I've seen reports that bttv 0.7.x crashes whereas 0.8.x works rock solid +for some people. Thus probably a small buglet left somewhere in bttv +0.7.x. I have no idea where exactly, it works stable for me and alot of +other people. But in case you have problems with the 0.7.x versions you +can give 0.8.x a try ... + + +hardware bugs +------------- + +Some hardware can't deal with PCI-PCI transfers (i.e. grabber => vga). +Sometimes problems show up with bttv just because of the high load on +the PCI bus. The bt848/878 chips have a few workarounds for known +incompatibilities, see README.quirks. + +Some folks report that increasing the pci latency helps too, +althrought I'm not sure whenever this really fixes the problems or +only makes it less likely to happen. Both bttv and btaudio have a +insmod option to set the PCI latency of the device. + +Some mainboard have problems to deal correctly with multiple devices +doing DMA at the same time. bttv + ide seems to cause this sometimes, +if this is the case you likely see freezes only with video and hard disk +access at the same time. Updating the IDE driver to get the latest and +greatest workarounds for hardware bugs might fix these problems. + + +other +----- + +If you use some binary-only yunk (like nvidia module) try to reproduce +the problem without. + +IRQ sharing is known to cause problems in some cases. It works just +fine in theory and many configurations. Neverless it might be worth a +try to shuffle around the PCI cards to give bttv another IRQ or make +it share the IRQ with some other piece of hardware. IRQ sharing with +VGA cards seems to cause trouble sometimes. I've also seen funny +effects with bttv sharing the IRQ with the ACPI bridge (and +apci-enabled kernel). + |