[mythtv-users] Kernel Crash when starting up in au0828-video.c line 895

[jrh]

On Apr 8, 2012, at 4:03 PM, Mark Lord wrote:

> On 12-04-08 04:01 PM, Mark Lord wrote:
>> On 12-04-08 02:34 AM, f-myth-users at media.mit.edu wrote:
>>>> Date: Sat, 07 Apr 2012 20:56:23 -0400
>>>> From: Mark Lord <mythtv at rtr.ca>
>>> 
>>>> I should add that, even with the above workarounds, there is STILL an issue
>>>> when mythbackend starts up:  If you have "multi-rec" enabled (more than one
>>>> virtual tuner per physical HVR-950Q), then the backend will have several
>>>> near-simultaneous "tune to initial channel" calls into the drivers.
>>> 
>>>> This will cause tuner failure.
>>> 
>>> I haven't been following this thread closely (not my hardware), but
>>> would it be possible to tune using an external tuner script that uses
>>> a mutex and some sleeps to avoid simultaneous tunes?  I have no idea
>>> if the way multirec tunes this hardware is amenable to breaking it
>>> out externally like that.
>> 
>> Mythtv doesn't offer external channel change scripts for all digital tuners,
>> dunno if it has the option for the 950Q or not.
>> 
>> But the place for the mutex is somewhere in one of the drivers that manages
>> the 950Q, probably in the au0828 driver.  At some point I suspect I'll go in
>> there and just fix the danged thing myself.  But for now, disabling multirec
>> keeps it working well enough.
> 
> Another related thing might be to fix mythbackend to NOT issue channel tuning
> requests to virtual tuners when the physical tuner is already tuned appropriately.


The way I was set up, I never enabled the digital side of the 950Q. I was only using the analog side. Also, I am using the 64 bit version.

I did try the 32 bit version, but had the same errors as below.. again only using the analog side, never adding the DVB ATSC tuner:


Apr  7 15:47:51 myth1204 mythbackend[1590]: I CoreContext v4lchannel.cpp:661 (SetInputAndFormat) V4LChannel(/dev/video0): SetInputAndFormat(1, NTSC) (v4l v2) input_switch: 0 mode_switch: 1



The messages below lead me to believe that maybe one of the ioctl calls in the v4l stuff may have had a null pointer passed to it.

Apr  7 15:47:50 myth1204 kernel: [   18.216226] ------------[ cut here ]------------
Apr  7 15:47:50 myth1204 kernel: [   18.216284] kernel BUG at /build/buildd/linux-3.2.0/drivers/media/video/au0828/au0828-video.c:895!
Apr  7 15:47:50 myth1204 kernel: [   18.216357] invalid opcode: 0000 [#1] SMP
Apr  7 15:47:50 myth1204 kernel: [   18.216394] CPU 0
Apr  7 15:47:50 myth1204 kernel: [   18.216412] Modules linked in: xc5000 tuner au8522 ppdev snd_usb_audio snd_atiixp snd_ac97_codec ac97_bus snd_pcm snd_hwdep snd_usbmidi_lib snd_seq_midi snd_rawmidi snd_seq_midi_event au0828 psmouse dvb_core snd_seq videobuf_vmalloc videobuf_core tveeprom v4l2_common snd_timer snd_seq_device videodev serio_raw v4l2_compat_ioctl32 radeon edac_core snd k8temp edac_mce_amd soundcore ttm snd_page_alloc drm_kms_helper i2c_piix4 drm i2c_algo_bit nfsd nfs lockd fscache auth_rpcgss nfs_acl sunrpc parport_pc mac_hid shpchp lp parport hid_apple usbhid hid 8139too usb_storage 8139cp pata_atiixp sata_sil floppy

Regards