On Fri, Dec 7, 2018 at 1:56 AM Guenter Roeck <linux@xxxxxxxxxxxx> wrote: > > On Thu, Dec 06, 2018 at 11:02:27AM +0800, Kyle Tso wrote: > > Current matching rules ensure that the voltage range of selected Source > > Capability is entirely within the range defined in one of the Sink > > Capabilities. This is reasonable but not practical because Sink may not > > support wide range of voltage when sinking power while Source could > > advertise its capabilities in raletively wider range. For example, a > > Source PDO advertising 3.3V-11V@3A (9V Prog of Fixed Nominal Voltage) > > will not be selected if the Sink requires 5V-12V@3A PPS power. However, > > the Sink could work well if the requested voltage range in RDOs is > > 5V-11V@3A. > > > > Maybe a graphical description would help ? > > Currently accepted: > |--------- source -----| > |----------- sink ---------------| > > Currently not accepted: > > |--------- source -----| > |----------- sink ---------------| > > |--------- source -----| > |----------- sink ---------------| > > |--------- source -----------------| > |------ sink -------| > Sorry for late reply. I was on vacation. Thanks for the suggestion. I will update the commit message. > > To improve the usability, change the matching rules to what listed > > below: > > a. The Source PDO is selectable if any portion of the voltage range > > overlaps one of the Sink PDO's voltage range. > > b. The maximum operational voltage will be the lower one between the > > selected Source PDO and the matching Sink PDO. > > c. The maximum power will be the maximum operational voltage times the > > maximum current defined in the selected Source PDO > > d. Select the Source PDO with the highest maximum power > > > > Signed-off-by: Kyle Tso <kyletso@xxxxxxxxxx> > > Makes sense to me. I am a bit concerned that it might cause odd regressions, > though. Did you test it with a few adapters ? > > With the expectation that you did, > > Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx> > Yes I have tested this patch with 3 different brands of adapters with PPS capabilities. thanks, Kyle
