> It would also help to check that it's not a kernel driver problem, by using
> the new VLC on the old Ubuntu kernel and vice versa.
>
I think we can put the kernel drivers out of the question, as another DVB-T
player ("kaffeine") is working as expected when tuning DVB-T channels. However,
I'll install another kernel version and try, if really needed.
> Can you please provide a threads stack trace from the middle of VLCs doing
> "nothing" for 20 seconds.
>
Don't know exactly how to do what you request :-( Through plain-old "strace" to
the vlc process I can see lots of the following looping (among other syscalls)
while "vlc" seems to be waiting for something:
[pid 28181] read(26,
"\1\1y\0\0\0\0\0y\0\240\4\0\0\0\0H\0\0\0H\377\36\0108\361\336\10\0\0\0\0",
4096) = 32
[pid 28181] read(26, 0xc378a18, 4096) = -1 EAGAIN (Resource temporarily
unavailable)
[pid 28181] read(26, 0xc378a18, 4096) = -1 EAGAIN (Resource temporarily
unavailable)
[pid 28181] read(26, 0xc378a18, 4096) = -1 EAGAIN (Resource temporarily
unavailable)
[pid 28181] read(26, 0xc378a18, 4096) = -1 EAGAIN (Resource temporarily
unavailable)
[pid 28181] read(26, 0xc378a18, 4096) = -1 EAGAIN (Resource temporarily
unavailable)
[pid 28181] read(26, 0xc378a18, 4096) = -1 EAGAIN (Resource temporarily
unavailable)
[pid 28181] read(26, 0xc378a18, 4096) = -1 EAGAIN (Resource temporarily
unavailable)
[pid 28181] read(26, 0xc378a18, 4096) = -1 EAGAIN (Resource temporarily
unavailable)
[pid 28181] read(26, 0xc378a18, 4096) = -1 EAGAIN (Resource temporarily
unavailable)
At another point in the "strace" file descriptor number 26 gets assigned to
another "vlc" thread:
[pid 28176] write(2, "[0xa7080d8] main video output de"..., 83) = 83
[pid 28176] socket(PF_FILE, SOCK_STREAM, 0) = 26
[pid 28176] connect(26, {sa_family=AF_FILE, path=@"/tmp/.X11-unix/X0"}, 20) = 0
[pid 28176] getpeername(26, {sa_family=AF_FILE, path=@"/tmp/.X11-unix/X0"},
[20]) = 0
[pid 28176] uname({sys="Linux", node="desktop", ...}) = 0
[pid 28176] access("/home/username/.Xauthority", R_OK) = 0
[pid 28176] open("/home/username/.Xauthority", O_RDONLY) = 28
[pid 28176] fstat64(28, {st_mode=S_IFREG|0600, st_size=382, ...}) = 0
[pid 28176] mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
-1, 0) = 0xb5695000
[pid 28176] read(28, "\0\0\0\4\300\250\1\2\0\0010\0\22MIT-MAGIC-COOKIE-1\0"...,
4096) = 382
[pid 28176] read(28, "", 4096) = 0
[pid 28176] close(28) = 0
[pid 28176] munmap(0xb5695000, 4096) = 0
[pid 28176] getsockname(26, {sa_family=AF_FILE, path=@"/tmp/.X11-unix/X0"},
[2]) = 0
[pid 28176] fcntl64(26, F_GETFL) = 0x2 (flags O_RDWR)
[pid 28176] fcntl64(26, F_SETFL, O_RDWR|O_NONBLOCK) = 0
[pid 28176] fcntl64(26, F_SETFD, FD_CLOEXEC) = 0
[pid 28176] poll([{fd=26, events=POLLIN|POLLOUT}], 1, -1) = 1 ([{fd=26,
revents=POLLOUT}])
[pid 28176] writev(26, [{"l\0\v\0\0\0\22\0\20\0\0\0", 12}, {"", 0},
{"MIT-MAGIC-COOKIE-1", 18}, {"\0\0", 2},
{"\1\227\363\232Y\230\242\210\343\341-\260\202[\350H", 16}, {"", 0}], 6) = 48
[pid 28176] read(26, 0xa6bc180, 8) = -1 EAGAIN (Resource temporarily
unavailable)
[pid 28176] poll([{fd=26, events=POLLIN}], 1, -1 <unfinished ...>
Seems quite strange, maybe my brief analysis of the problem is completely
wrong. Please advice on taking a "threads stack trace" as previously requested.
Thank you.
--
Long delays tuning DVB-T channels
https://bugs.launchpad.net/bugs/518478
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