[linux-dvb] [DVB] MT352 (Nebula PCI) playback freezing with a readreg errorafter a random time on FC6.

Rafael Moslin raf at moslin.com
Sat Feb 3 11:50:17 CET 2007

Apologies for missing out on any conventions in this post but I'm pretty
new to Linux and lists. I have posted this same message to the
video4linux-list at redhat.com list but this list got recommended as being
a better one.

I have a Nebula Electronics PCI DVB-T (Zarlink MT352) card running on an
Asus AM2 mobo, has been working just fine for a couple of months on
Fedora Core 6 but possibly after an automatic update to
kernel-2.6.18-1.2798.fc6.x86_64 but I'm not sold that this was the
cause, it now only works for anything between 5 minutes to an hour
before the picture freezes. If I modprobe -r dvb_bt8xx followed by
modprobe dvb_bt8xx I buy myself some more time however on occasions the
removal of dvb_bt8xx has caused the machine to hang.

I do normally use MythTV but uninstalled it and installed Kaffeine to
make testing a bit easier, and that displays the video just fine albeit
I have noticed the sound gradually going out of sync. I have since
updated to 2.6.19-1 but with no change in behaviour. when checking the
dmesg output after the picture freeze it complains that it cannot write
to various registers on the DVB card. The PC has a small partition with
Windows XP (for testing) and that has no problems with the card at all,
running happily for days ruling out a hardware problem with the DVB

I really do not know where to go next, and feel really frustrated by my
lack of under the hood Linux knowledge.

Tried to rollback the previous kernel, forward and a cartwheel, still
the same, a bit of relevant output from dmesg that might cause a passing
soul to have a lightbulb moment:

Linux video capture interface: v2.00
bttv: driver version 0.9.16 loaded
bttv: using 8 buffers with 2080k (520 pages) each for capture
eth0: forcedeth.c: subsystem: 01043:816a bound to 0000:00:14.0
i2c_adapter i2c-0: nForce2 SMBus adapter at 0x4c00
i2c_adapter i2c-1: nForce2 SMBus adapter at 0x4c40
EDAC MC0: Giving out device to k8_edac Athlon64/Opteron: DEV
shpchp: Standard Hot Plug PCI Controller Driver version: 0.4
bttv: Bt8xx card found (0).
ACPI: PCI Interrupt Link [APC2] enabled at IRQ 17
ACPI: PCI Interrupt 0000:04:09.0[A] -> Link [APC2] -> GSI 17 (level,
low) -> IRQ 17
bttv0: Bt878 (rev 17) at 0000:04:09.0, irq: 17, latency: 32, mmio:
bttv0: detected: Nebula Electronics DigiTV [card=104], PCI subsystem ID
is 0071:0101
bttv0: using: Nebula Electronics DigiTV [card=104,insmod option]
bttv0: gpio: en=00000000, out=00000000 in=00ffffcb [init]
bttv0: using tuner=-1
bttv0: registered device video0
bttv0: registered device vbi0
bttv0: PLL: 28636363 => 35468950 .. ok
bttv0: add subdevice "dvb0"
input: bttv IR (card=104) as /class/input/input2
bttv-input: bttv IR (card=104) detected at pci-0000:04:09.0/ir0

lsmod | grep dvb:

dvb_bt8xx 27461 6
dvb_core 101105 1 dvb_bt8xx
bt878 21001 1 dvb_bt8xx
dvb_pll 25157 1 dvb_bt8xx
bttv 224309 2 dvb_bt8xx,bt878
i2c_core 34369 10
i2c_ec,mt352,nxt6000,dvb_bt8xx,nvidia,dvb_pll,bttv ,i2c_algo_bit,tveeprom,i2c_nforce2


04:09.0 Multimedia video controller: Brooktree Corporation Bt878 Video
Capture (rev 11)
04:09.1 Multimedia controller: Brooktree Corporation Bt878 Audio Capture
(rev 11)

As soon as the picture freezes I get this from dmesg, same line repeated
about fifety times:

mt352_read_register: readreg error (reg=0, ret==-5)

If it did not work full stop, great, something to look for, but work and
then stop is not easy to track down and I have run out of ideas so would
really appreciate any help in where to look or even a direction to head

No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.1.411 / Virus Database: 268.17.21/665 - Release Date: 02/02/2007

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