Hi,
First of all, sorry for not correctly replying to the thread. I just
subscribed to the list yesterday, so I do not have the message in my
inbox.
I am referring to this message:
https://www.spinics.net/lists/linux-media/msg140286.html
My system also suffered from the problem that, with Kernel 4.18 my DVB
card became unresponsive after a few hours. I am using tvheadend as a
video recorder, and with Kernel 4.18, tvheadend started missing
recordings, with log messages like the following:
linuxdvb: Silicon Labs Si2168 : DVB-C #1 - poll TIMEOUT
subscription: 0163: service instance is bad, reason: No input detected
subscription: 0162: service instance is bad, reason: No input detected
subscription: 0163: No input source available for subscription "DVR:
..." to channel "..."
In this state, the DVB card was not usable until unloading the cx23885
module and reloading it -- just to fail again few hours later.
Also, I noticed log messages like these, not directly correlatable to
the failures (not at the same time as the failed recordings, and
sometimes also working recordings after such a log message).
kernel: cx23885 0000:02:00.0: dma in progress detected 0x00000001
0x00000001, clearing
Nevertheless, the patch introducing the log message seems also to cause
the failure:
[PATCH 3/5] cx23885: Ryzen DMA related RiSC engine stall fixes
https://www.spinics.net/lists/linux-media/msg133899.html
I never suffered the problem the patch is trying to solve (card used to
work flawlessly for months). To see if that patch is not only the
messenger, but also the culprit, I built a custom kernel based on the
kernel-4.18.9-200.fc28.x86_64 source RPM from Fedora 28, only applying
the patch above in reverse -- and did not have a single failure for > 48
hours now.
Since the author tried to solve a problem, and maybe even did for his
system, I guess reversing the patch alone is not a proper solution for
everyone. And since the author did submit this patch, I guess he also
did not suffer from the problem I have right now... so a
fits-for-all-solution might be harder to find, also because the failure
is not immediate.
Unfortunately I don't know enough about the code in question (or kernel
development as whole), so I have no clue how to analyze (or even fix)
this any further. What I can offer is to test modified versions of the
patch above on my computer, as it does not seem to affect everyone.
Some information on my system:
- HP Microserver G7 N54L with AMD Turion II Neo CPU
- DVBSky T982 PCI-E card with dual DVB-T/C tuners, identifying as
02:00.0 Multimedia video controller: Conexant Systems, Inc. CX23885
PCI Video and Audio Decoder (rev 04)
Subsystem: DVBSky T982
Flags: bus master, fast devsel, latency 0, IRQ 16, NUMA node 0
Memory at fe600000 (64-bit, non-prefetchable) [size=2M]
Capabilities: <access denied>
Kernel driver in use: cx23885
Kernel modules: cx23885
- Fedora 28, currently with a custom kernel, usually with the most
recent "stock" fedora kernel.
- kernel-4.18.9-200.fixdvb.fc28.x86_64 ("fixdvb" being my local
extraversion, only difference to the original kernel: the reversed patch
above)
- tvheadend-4.2.6-1.fc28.x86_64
Regards,
Markus
