Re: Rpi4B needs power off reboot for TV hat

In message <wwva56dfkww.fsf@LkoBDZeT.terraraq.uk>
          Richard Kettlewell <invalid@invalid.invalid> wrote:

Joerg Walther <joerg.walther@magenta.de> writes:

The Natural Philosopher wrote:

 

Finally identified something I had been suspecting for some time.
Issuing a 'reboot' command results in tvheadend unable to find the DVB
adapter, but a power off reset finds it.

 
I had similar behaviour with a network card some while ago. Apparently
the reboot leaves the device in a state which makes it impossible for the
OS to detect it after the reboot. This actually is a bug in the driver
for the adapter, which you could report to the maintainer. When you
switch if off completely, "something" is set to standard values, thus
making the DVB adapter again available for the OS.

 
That sounds more like a bug in the device? i.e. not honoring the reset
signal from the host after reboot.

Doesn't it suggest that the driver, when run from a reboot, assumes
that the device has had a hardware reset, which won't have happened
on a reboot without power cycle?

It's common for devices to have a method to software reset them, though
the results may not be identical to a hardware reset.

David