[4.16,REGRESSION,fix] Revert "typec: tcpm: Only request matching pdos"

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

On Tue, Mar 06, 2018 at 10:50:05AM +0100, Hans de Goede wrote:
> Commit 57e6f0d7b804 ("typec: tcpm: Only request matching pdos") is causing
> a regression, before this commit e.g. the GPD win and GPD pocket devices
> were charging at 9V 3A with a PD charger, now they are instead slowly
> discharging  at 5V 0.4A, as this commit causes the ports max_snk_mv/ma/mw
> settings to be completely ignored.
> 
> Arguably the way to fix this would be to add a PDO_VAR() describing the
> voltage range to the snk_caps of boards which can handle any voltage in
> their range, but the "typec: tcpm: Only request matching pdos" commit
> looks at the type of PDO advertised by the source/charger and if that
> is fixed (as it typically is) only compairs against PDO_FIXED entries
> in the snk_caps so supporting a range of voltage would require adding a
> PDO_FIXED entry for *every possible* voltage to snk_caps.
> 
> AFAICT there is no reason why a fixed source_cap cannot be matched against
> a variable snk_cap, so at a minimum the commit should be rewritten to
> support that.
> 
> For now lets revert the "typec: tcpm: Only request matching pdos" commit,
> fixing the regression.
> 
> Cc: Badhri Jagan Sridharan <badhri@google.com>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>

You are correct. The patch should be rewritten.

Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>


Thanks,