diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/video4linux/bttv/README.freeze |
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 000000000000..51f8d4379a94 --- /dev/null +++ b/Documentation/video4linux/bttv/README.freeze | |||
@@ -0,0 +1,74 @@ | |||
1 | |||
2 | If the box freezes hard with bttv ... | ||
3 | ===================================== | ||
4 | |||
5 | It might be a bttv driver bug. It also might be bad hardware. It also | ||
6 | might be something else ... | ||
7 | |||
8 | Just mailing me "bttv freezes" isn't going to help much. This README | ||
9 | has a few hints how you can help to pin down the problem. | ||
10 | |||
11 | |||
12 | bttv bugs | ||
13 | --------- | ||
14 | |||
15 | If some version works and another doesn't it is likely to be a driver | ||
16 | bug. It is very helpful if you can tell where exactly it broke | ||
17 | (i.e. the last working and the first broken version). | ||
18 | |||
19 | With a hard freeze you probably doesn't find anything in the logfiles. | ||
20 | The only way to capture any kernel messages is to hook up a serial | ||
21 | console and let some terminal application log the messages. /me uses | ||
22 | screen. See Documentation/serial-console.txt for details on setting | ||
23 | up a serial console. | ||
24 | |||
25 | Read Documentation/oops-tracing.txt to learn how to get any useful | ||
26 | information out of a register+stack dump printed by the kernel on | ||
27 | protection faults (so-called "kernel oops"). | ||
28 | |||
29 | If you run into some kind of deadlock, you can try to dump a call trace | ||
30 | for each process using sysrq-t (see Documentation/sysrq.txt). ksymoops | ||
31 | will translate these dumps into kernel symbols too. This way it is | ||
32 | possible to figure where *exactly* some process in "D" state is stuck. | ||
33 | |||
34 | I've seen reports that bttv 0.7.x crashes whereas 0.8.x works rock solid | ||
35 | for some people. Thus probably a small buglet left somewhere in bttv | ||
36 | 0.7.x. I have no idea where exactly, it works stable for me and alot of | ||
37 | other people. But in case you have problems with the 0.7.x versions you | ||
38 | can give 0.8.x a try ... | ||
39 | |||
40 | |||
41 | hardware bugs | ||
42 | ------------- | ||
43 | |||
44 | Some hardware can't deal with PCI-PCI transfers (i.e. grabber => vga). | ||
45 | Sometimes problems show up with bttv just because of the high load on | ||
46 | the PCI bus. The bt848/878 chips have a few workarounds for known | ||
47 | incompatibilities, see README.quirks. | ||
48 | |||
49 | Some folks report that increasing the pci latency helps too, | ||
50 | althrought I'm not sure whenever this really fixes the problems or | ||
51 | only makes it less likely to happen. Both bttv and btaudio have a | ||
52 | insmod option to set the PCI latency of the device. | ||
53 | |||
54 | Some mainboard have problems to deal correctly with multiple devices | ||
55 | doing DMA at the same time. bttv + ide seems to cause this sometimes, | ||
56 | if this is the case you likely see freezes only with video and hard disk | ||
57 | access at the same time. Updating the IDE driver to get the latest and | ||
58 | greatest workarounds for hardware bugs might fix these problems. | ||
59 | |||
60 | |||
61 | other | ||
62 | ----- | ||
63 | |||
64 | If you use some binary-only yunk (like nvidia module) try to reproduce | ||
65 | the problem without. | ||
66 | |||
67 | IRQ sharing is known to cause problems in some cases. It works just | ||
68 | fine in theory and many configurations. Neverless it might be worth a | ||
69 | try to shuffle around the PCI cards to give bttv another IRQ or make | ||
70 | it share the IRQ with some other piece of hardware. IRQ sharing with | ||
71 | VGA cards seems to cause trouble sometimes. I've also seen funny | ||
72 | effects with bttv sharing the IRQ with the ACPI bridge (and | ||
73 | apci-enabled kernel). | ||
74 | |||