Re: [PATCHv2 3/5] pulse8-cec: new driver for the Pulse-Eight USB-CEC Adapter

[Lars Op den Kamp <lars@opdenkamp.eu>]

Hi Hans,

On 11-07-16 12:02, Hans Verkuil wrote:
> Hi Lars,
>
> On 07/11/2016 11:41 AM, Lars Op den Kamp wrote:
>> Hi Hans,
>>
>> just did a quick scan of this patch.
>>
>> The code should work on any firmware >= v2 revision 8, though older
>> versions may return 0 when the build date is requested. I believe I
>> added that in v3. Might want to add a !=0 check before writing to the log.
>>
>> The CEC adapter has an "autonomous mode", used when it's not being
>> controlled by our userspace application or this kernel driver. It'll
>> respond to some basic CEC commands that allow the PC to be woken up by TV.
>> If the adapter doesn't receive a MSGCODE_PING for 30 seconds when it's
>> in "controlled mode", then it'll revert to autonomous mode and it'll
>> reset all states internally.
> Ah, that was rather obscure. Good to know.
>
> What I do now (and that seems to work) is that in the pulse8_setup I turn
> off the autonomous mode and then write that new setting to the EEPROM. After
> that it looks like the autonomous mode stays off. Is that correct?
Correct, that'll work too, but I suggest you don't do that and update 
the eeprom values like we do in userspace. That'll allow the adapter to 
wake up the PC when the kernel module isn't running. Disabling 
autonomous mode will prevent that from working. You can only write to 
the eeprom once every 10 seconds by the way.

>
> The autonomous mode really doesn't work well with the framework as it is
> today.
>
> CEC framework support for 'wakeup on CEC command' is something that is planned
> for the future.
The autonomous mode is only really meant for waking up the PC, from S3 
with the USB version and all modes with the internal version for Intel 
boards. It should be disabled as long as the userspace application or 
kernel module is running, by sending MSGCODE_SET_CONTROLLED 1 and then 
send a poll before the 30 second timeout times out. Then, when the 
kernel module stops using the module, when the system powers off or goes 
to standby, you send a MSGCODE_SET_CONTROLLED 0 and then close the 
connection. The adapter will then take over, allowing the TV to wake up 
the PC again.

thanks, Lars