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Based on kernel version 3.15.4. Page generated on 2014-07-07 09:05 EST.

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).
31	This way it is possible to figure where *exactly* some process in "D"
32	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 a lot 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).
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