[mythtv-users] FE artwork periodically flashes away

[Mark Perkins]

> -----Original Message-----
> From: mythtv-users-bounces at mythtv.org [mailto:mythtv-users-
> bounces at mythtv.org] On Behalf Of Joseph Fry
> Sent: Tuesday, 4 November 2014 2:17 PM
> To: Discussion about MythTV
> Subject: Re: [mythtv-users] FE artwork periodically flashes away
> 
> 
> 
>> On Mon, Nov 3, 2014 at 8:07 PM, Hika van den Hoven <hikavdh at gmail.com>
>> wrote:
>> 
>> 
>>Hoi Mark,
>> 	Just a thought, have you looked into issues concerning powersave?
>> Also
>> 	is the metadata on another physical disk, that for instance spins
>> down.
> 
> 
> 
> 
> The error doesn't point at a file being unavailable.
> 
> Looking at the code for playbackbox.cpp, it looks like the handlepreview
> event is getting spawned multiple times... almost as though you moved away
> and back to the item.
> 
> I don't know the code well enough to understand what would spawn that
> event, other than moving up or down the list, but I suspect that it's not
> related to your hdd spinning down or the file being otherwise inaccessible.
> 
> I suspect that it is related to powersaving.
> 
> Check your frontends  "FrontendIdleTimeout" value (you can see it in the
> general setup screen (I think) or in mythweb (in the settings > mythtv page
> after selecting the frontend from the dropdown).  I wonder if perhaps when
> this timer expires it triggers something that takes the focus away from the
> frontend briefly... setting off a new handlepreview event when the focus
> returns?  Maybe it tries several times and gives up.
> 
> Perhaps you didn't disable xscreensaver as completely as you think, and it's
> stealing the focus over and over before finally failing?  You could try disabling
> xscreensaver by stopping the service altogether?
> 
> I could be way off base, this is just speculation, but something is definitely
> triggering these events multiple times before giving up.
> 
> 
> 
Thanks Hika and Joseph for the responses, much appreciated.

I've managed to have a bit of luck here. I started trying to time and count the flashes to identify a pattern. Turns out that the number of flashes equalled the number of recordings in the Delete recording group.

Of course at that point the immediate question was - why are there recordings stuck in the Delete group? And on a lucky tangent I went.

About 6 months ago my recording drives started to get full. So I moved a pile of recordings that were shows we watch when there is nothing else to watch over to a NAS. I thought everything was working fine but it turns out MythBE could not 'unlink' the recordings as part of the delete process. I could still watch the recordings, and the mythtv user (that runs my backend) could rm / cp / mv the recordings but MythBE could not 'unlink' (whatever 'unlink' actually means in practice). So every time it tried to 'unlink' I got that series of flashes on the FE. As we gradually watched (and deleted) more of those shows the problem became more obvious (more flashes).

I double checked permissions on the folders but everything looked fine.

I checked my /etc/fstab file to see how the CIFS shares were mounted. This was the original line:

//192.168.1.22/ServerThree/ServerTwo        /media/servertwo        cifs    credentials=**deleted**,gid=1001,uid=1001,nounix,iocharset=utf8,file_mode=0777,dir_mode=0777     0       0

I did a quick read on the 'nounix' option and it sounded like a possible candidate for what was going on ("nounix" option disable CIFS Unix Extensions so that no UNIX ACL, path and lock will be used - so maybe MythBE couldn’t lock file to unlink or something?) anyway I removed 'nounix' and remounted and voila - over the next 5min all the recordings were deleted. And once the to-be-deleted recordings were gone the flashing stopped.

I still get the occasional flash but only a single flash and I assume it is only shortly after I delete a recording.

For the record these are the messages I was getting in the backend log about once (one block) every 15minutes or so:

2014-11-04 11:23:55.215723 N [3267/3398] Expire autoexpire.cpp:641 (SendDeleteMessages) - Expiring 2136 MB for 1099 at 2014-07-20T09:57:00Z => "Hamish And Andy's Gap Year South America"
2014-11-04 11:24:00.278920 E [3267/13004] DeleteThread mainserver.cpp:2307 (OpenAndUnlink) - Error deleting '/media/serverthree_s1/Myth_Temp_Rec/1009_20131003110000.mpg' could not unlink
                        eno: Device or resource busy (16)
2014-11-04 11:24:00.279584 E [3267/13004] DeleteThread mainserver.cpp:2279 (DeleteFile) - Delete Error '/media/serverthree_s1/Myth_Temp_Rec/1009_20131003110000.mpg'
                        eno: Device or resource busy (16)
2014-11-04 11:24:00.280975 E [3267/13004] DeleteThread mainserver.cpp:2059 (DoDeleteThread) - Error deleting file: /media/serverthree_s1/Myth_Temp_Rec/1009_20131003110000.mpg. Keeping metadata in database.

The only catch to all this - I'm not clear on exactly how the delete failure translates into metadata flashing on the screen. There is clearly a link (at least on my setup, sample size = 1), but the mechanics of that part elude me.