Forgive me if this was mentioned just last month. This list seems to have
no search option and I am always sure to scour the internet to the best
of my ability before intruding. That said:
When I watch TV in Linux using 2.6.0 and bttv (tvtime, but it happens in
all tv-playing applications so it's a driver issue), there is a severe
tearing effect. Like horizontal brown lines scanning and the text
"shakes" and "jumps." Imagine having vsync set wrong in a game from the
1999 era -- it's like that, and very obnoxious. The tvtime people were
very helpful but could not think of any solution and we tried every
deinterlacing idea that could be conceived.
So what came to mind next was an IRQ problem and although they didn't
seem to be there when I initially noticed the tearing, nevertheless
'dmesg' shows 30-40 of these shortly after starting tvtime:
bttv0: skipped frame. no signal? high irq latency?
[main=ef6f000,o_vbi=ef6f018,rc=991701c]
bttv0: skipped frame. no signal? high irq latency?
[main=ef6f000,o_vbi=ef6f018,rc=991701c]
bttv0: skipped frame. no signal? high irq latency?
[main=ef6f000,o_vbi=ef6f018,rc=991701c]
..
Please note that I do NOT notice any framedropping problems. The problem
is all in the tearing. It is most noticeable on places like CNN Headline
News where the text is warping to all hell, but also note that it's a
screen-wide problem: it's equally as noticeable while watching Roseanne
on Nick@Nite, for instance, which has no text anywhere. The problem
seems to worsen slightly in fullscreen but is omnipresent.
I have tried the following:
- Googling (very few other people have had the problem, nobody had
solutions)
- Swapping positions of PCI cards to no avail
- Disabling/enabling PCI Delay Transaction in the BIOS
- Turning off lirc_dev, lirc_gpio (lirc_gpio is for the remote -- which
is also sketchy, btw, but likely an unrelated problem) and all other
modules related to bttv/lirc except bttv itself
- 2.6.0-test11, now using 2.6.0 final
- bttv with kraxel's patches from the website, as well as without
- every deinterlacing/framerate/video option in tvtime
- running it as root
- disabling other PCI device modules such as my network card (3c59x)
- bttv starts with gbuffers=4 -- tried 2 & 8, tried playing with latency
insmod options
- changing monitor resolution
- changing rtc-max-user-freq options around (this probably reveals that
I am not very knowledgable about this sort of thing)
No-go on any of the above and I should note that it works beautifully in
Windows, so I do not think it could be a signal or cable line issue.
Specifications:
Athlon XP 1700+ (1.47ghz)
GeForce 3 Ti200
Leadtek WinFast 2000 XP Deluxe (bt878)
bttv 0.9.12
card 34, tuner 2 (also works with 17)
2.6.0 final
1280x1024@75hz
NVIDIA 4496 drivers (tried 4620) with GLX enabled
X 4.3.0 (Gentoo)
cat /proc/interrupts
CPU0
0: 31100876 XT-PIC timer
1: 9241 XT-PIC i8042
2: 0 XT-PIC cascade
5: 0 XT-PIC EMU10K1
8: 8839067 XT-PIC rtc
10: 273790 XT-PIC eth0
11: 2597522 XT-PIC nvidia
12: 637750 XT-PIC uhci_hcd, uhci_hcd, bttv0
14: 167718 XT-PIC ide0
15: 35 XT-PIC ide1
NMI: 0
ERR: 0
This is a tough problem, it seems, and I'll answer any questions you
have if you have any ideas. Thanks,
- Cody
