I'm getting intermittent continuity errors on tuners connected to TVHeadend >on a Pi4.
For several years I've been running TVHeadend on Pi4, with a PCTV 491e
DVB-S2 tuner and a Hauppauge WinTV DualHD DVB-T2 tuner, writing to a USB >caddy containing a spinning HDD. All the USB devices are connected to >separate USB sockets on the Pi: I'm not multiplexing several devices via a >hub onto a single USB socket on the Pi.
Mostly this works perfectly, but every now and again I get continuity
errors, maybe 50-150 per hour of recording, when normally I get zero for >DVB-S2, and 0 to 5 per hour for DVB-T2. The reported signal strength and SNR >when I get glitches (on the Status | Stream tab) seem the same as normal: >around 11-12 dB (SNR) and -30 dBm (strength) for satellite and around 25 dB
/ -42 dBm for terrestrial.
The HDD is a standard Sata 3 spinning HDD: Samsung HD161HJ, and the powered >USB caddy is a WAVLINK one. (*)
I'm wondering whether it's not so much a reception problem as a USB-transfer >problem, either from tuner to Pi or Pi to HDD.
Once the problem happens, it affects all tuners and all recordings made
until I reboot (without powering down Pi or HDD caddy). Rebooting sets the >Status | Stream error counters to zero, but more importantly seems to
prevent future errors occurring - for a few days or weeks. I've got into the >habit of rebooting the Pi every few days, just in case...
Before I go through the hassle of changing components (tuners, USB caddy >interface, HDD) one by one, I wanted to check whether anyone else with a >similar setup has experienced (and maybe fixed) this problem.
Are there any solid-state HDDs which are suitable for repeated writes and >then deletes of large files, such as you'd get on a PVR. I tend to use the >Pi's HDD just for temporary storage, copying and editing out commercials in >recorded programmes onto a Windows PC for long-term storage. Hence the Pi's >HDD does not need to be large - 100 GB is fine.
(*) I found out by bitter experience that a powered hub with a USB HDD (as >opposed to a USB-SATA interface in a caddy containing a SATA HDD) had >problems with the Pi 4: the Pi would not boot if the USB hub was powered on >at the time (as would happen if the power to everything came back on >simultaneously after a power cut). When the Pi had hung, it would resume >booting the instant the powered hub was unplugged either from the Pi's USB
or else from its power supply. This seems to be a Pi 4 "funny": the same USB >hub worked fine with a Pi 3B+. But that's an aside.
I'm wondering whether it's not so much a reception problem as aAny windmills around? play havoc with radio and TV reception..
USB-transfer problem, either from tun
OK, not been here for a long time..
will try to share my experience with my PI4 with 4 GB memory.
I have a 3.something Toshiba TB USB harddisk on it via a Sitecom powered
USB hub,
recording 5 security cameras 24/7, plus some other recordings, plus background music player, plus Chromium browser.
I had similar mysterious problems and it had to do with the Pi cache.
After adding this to crontab;
0,15,30,45 * * * * /bin/echo 3 > /proc/sys/vm/drop_caches
clears the cache every 15 minutes, I have not seen any problems.
# uptime
19:42:20 up 59 days, 10:27, 15 users, load average: 0.26, 0.61, 0.88
My Pi4 8 GB with similar Toshiba harddisk on similar USB hub also boots normally.
"Jan Panteltje" <pNaonStpealmtje@yahoo.com> wrote in message >news:sqst34$o9l$1@dont-email.me...
OK, not been here for a long time..
will try to share my experience with my PI4 with 4 GB memory.
I have a 3.something Toshiba TB USB harddisk on it via a Sitecom powered
USB hub,
recording 5 security cameras 24/7, plus some other recordings, plus
background music player, plus Chromium browser.
I had similar mysterious problems and it had to do with the Pi cache.
After adding this to crontab;
0,15,30,45 * * * * /bin/echo 3 > /proc/sys/vm/drop_caches
clears the cache every 15 minutes, I have not seen any problems.
# uptime
19:42:20 up 59 days, 10:27, 15 users, load average: 0.26, 0.61, 0.88
I'll give that crontab line a try. A cache-clearing problem does sound >plausible. I wonder what effect it would have if a cache was cleared while a >recording was being made. Only one way to find out... :-)
My Pi4 8 GB with similar Toshiba harddisk on similar USB hub also boots
normally.
The problem with hanging on booting seems to be reported by quite a lot of >people on the RasPi 4 forums. There have been a number of theories, such as >that the Pi 4 doesn't like to boot if the USB +5V line has power on it (from >the PSU of a powered up feeding "up" the cable). However I proved that this
was not the cause of my problem by making a special USB cable between Pi and >hub with the data lines intact but the +5V line cut, to prevent back >powering. I decided to cut my losses and use a powered USB/SATA interface to >a SATA disc instead.
That problem with the radar site sounds pretty serious if it is taking out >satellite reception for people nearby. I imagine the radar uses different >frequencies to the 10-13 GHz used by DVB-S(2) but something is generating >harmonics of the radar frequency which *are* in the 10-13 range.
I'm getting intermittent continuity errors on tuners connected to
TVHeadend on a Pi4.
The problem with hanging on booting seems to be reported by quite a lot
of people on the RasPi 4 forums. There have been a number of theories,
such as that the Pi 4 doesn't like to boot if the USB +5V line has power
on it (from the PSU of a powered up feeding "up" the cable). However I
proved that this was not the cause of my problem by making a special USB cable between Pi and hub with the data lines intact but the +5V line
cut, to prevent back powering. I decided to cut my losses and use a
powered USB/SATA interface to a SATA disc instead.
On 02/01/2022 17:51, NY wrote:
I'm wondering whether it's not so much a reception problem as aAny windmills around? play havoc with radio and TV reception..
USB-transfer problem, either from tun
On 02/01/2022 19:58, NY wrote:
The problem with hanging on booting seems to be reported by quite a lot
of people on the RasPi 4 forums. There have been a number of theories,
such as that the Pi 4 doesn't like to boot if the USB +5V line has power
on it (from the PSU of a powered up feeding "up" the cable). However I
proved that this was not the cause of my problem by making a special USB
cable between Pi and hub with the data lines intact but the +5V line cut,
to prevent back powering. I decided to cut my losses and use a powered
USB/SATA interface to a SATA disc instead.
I can't quickly find the reference but I read somewhere that the USB data lines could leak enough power back into the Pi to prevent it doing a full cold start.
"Dave" <dave@cyw.uklinux.net> wrote in message >news:squp45$v53$1@dont-email.me...
On 02/01/2022 19:58, NY wrote:
The problem with hanging on booting seems to be reported by quite a lot
of people on the RasPi 4 forums. There have been a number of theories,
such as that the Pi 4 doesn't like to boot if the USB +5V line has power >>> on it (from the PSU of a powered up feeding "up" the cable). However I
proved that this was not the cause of my problem by making a special USB >>> cable between Pi and hub with the data lines intact but the +5V line cut, >>> to prevent back powering. I decided to cut my losses and use a powered
USB/SATA interface to a SATA disc instead.
I can't quickly find the reference but I read somewhere that the USB data
lines could leak enough power back into the Pi to prevent it doing a full
cold start.
I'm not sure why it happens on my Pi with my powered hub even when the lead >has its +5V line cut to prevent this happening. And I'm not sure why the Pi
4 is sensitive to it when the 3B+ (with the same hub) isn't.
I wonder if, as you say, the hub also holds the *data* lines high or low, >instead of allowing them to float at whatever voltage the Pi sets them at.
If so, you can't combat it just by cutting the +5V line.
I'm surprised the PiHut haven't produced a list of known-good hubs so you >know which to buy (and which not to buy).
It's only a problem if you need to inject power to a spinning USB drive, >rather than letting the computer supply its power as you'd do with a PC, >laptop or Mac. I imagine SSDs use sufficiently little power that they can be >powered directly from a Pi.
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