Re: cec kernel oops with pulse8 usb cec adapter

[Hans Verkuil <hverkuil@xs4all.nl>]

On 11/14/18 14:00, Torbjorn Jansson wrote:

<snip>

> since there now is a patch that appears to be working and fixing this problem 
> i'd like to ask for some troubleshooting advice with another cec issue i have 
> that i haven't figured out why it is happening and exactly whats causing it.
> 
> i'm not sure if it is a hardware issue or a software issue or both.
> 
> this is what is happening:
> i have a script that polls the tv for current status by running:
> cec-ctl --to=0 --give-device-power-status
> after a fresh reboot this works fine for a while then sometime later it stops 
> working and errors with:
> -
> # cec-ctl --to=0 --give-device-power-status
> Driver Info:
>          Driver Name                : pulse8-cec
>          Adapter Name               : serio0
>          Capabilities               : 0x0000003f
>                  Physical Address
>                  Logical Addresses
>                  Transmit
>                  Passthrough
>                  Remote Control Support
>                  Monitor All
>          Driver version             : 4.18.16
>          Available Logical Addresses: 1
>          Physical Address           : 1.4.0.0
>          Logical Address Mask       : 0x0800
>          CEC Version                : 2.0
>          Vendor ID                  : 0x000c03
>          Logical Addresses          : 1 (Allow RC Passthrough)
> 
>            Logical Address          : 11 (Playback Device 3)
>              Primary Device Type    : Playback
>              Logical Address Type   : Playback
>              All Device Types       : Playback
>              RC TV Profile          : None
>              Device Features        :
>                  None
> 
> 
> Transmit from Playback Device 3 to TV (11 to 0):
> CEC_MSG_GIVE_DEVICE_POWER_STATUS (0x8f)
>          Sequence: 119437 Tx Timestamp: 865389.535s
>          Tx, Error (1), Max Retries
> -
> 
> once this happens i can never get back any status and also running:
> cec-ctl -M
> gives me a lot of:
> Transmitted by Playback Device 3 to TV (11 to 0): 
> CEC_MSG_GIVE_DEVICE_POWER_STATUS (0x8f)
>          Tx, Error (1), Max Retries
> once for every run of my status checking script.
> 
> i know polling like this is not the best option and a better way would be to 
> listen for events and then take action when status changes but that's not 
> easily doable with what i need it for.
> 
> anyway, once i start getting the above errors when i poll it will not give me 
> back any good status any more (everything errors out)
> 
> also sending commands to tv to turn on or off like:
> cec-ctl --to=0 --image-view-on
> or
> cec-ctl --to=0 --standby
> doesn't work.
> 
> BUT if i remove power to tv and wait for standby led to go out completely then 
> power it back on i can use above two commands to turn on/off the tv even when 
> they return errors and i still can't poll for current status.
> 
> so even with the errors always returned at this stage the on/off commands still 
> gets sent and works.
> 
> do you think this behavior is a sw or hw issue or both?

Does 'cec-ctl --to=0 --give-device-power-status' eventually fail even if the TV is
on all the time? Or does it only fail if the TV goes to standby or has been in
standby for a very long time?

This error ('Tx, Error (1), Max Retries') indicates that the pulse-eight returns
transmit errors suggesting that the CEC line is locked (always high or low).

> 
> 
> if i'm not mistaken i could unplug usb cable to pulse8 cec adapter and reinsert 
> to make it work properly again (no errors and correct response like a fresh start)
> but i'm not 100% sure of this.
> when i tried it now i get a new kernel oops:
> -
> [866129.392139] usb 7-2: USB disconnect, device number 3
> [866129.409568] cdc_acm 7-2:1.1: acm_start_wb - usb_submit_urb(write bulk) 
> failed: -19
> [866129.409576] cdc_acm 7-2:1.1: acm_start_wb - usb_submit_urb(write bulk) 
> failed: -19
> [866129.409635] WARNING: CPU: 10 PID: 1571 at drivers/media/cec/cec-adap.c:1243 

Not a kernel oops, just a warning. The pulse-eight driver has a small bug
that causes this warning, but it does not affect the CEC behavior in any way.

I'll post a patch.

Regards,

	Hans