isp1707 & bq2415x marriage ...passing the original thought

isp1707 perform automatic charger detection if ( CHGR_det_EN_N is true ) and because this pin is tied to ground on n900 the isp1707 chip perform this detection and assert 1 to CHGR_DET pin
what BQ chip is doing with this ? well some things happen when an charger is connected
1) charger is connected and vbus rise to 5v
2) isp1707 perform charger detection and assert CHGR_DET = true AFTER t_chgr_det_dbnc time ( 25-113 ms )
bq asic start charging with initial current 100 mA
3) IF isp1707 detect low power charger ( hub 100/ 500 mA or computer 500 mA ) and will NOT assert CHGR_DET true leaving bq chip to charge battery with 100 mA. some reports are on forum saying charging from a hub take long time so here is the reason
( i can say more here )
IF isp1707 detect high power charger ( D+ and D- shorted ) will assert CHGR_DET = true and BQ chip switch high power mode ( 500 mA - 1250 mA )

until now all ok !
but ... if no charger is attached and sometimes we are blessed with host mode BQ chip start boost mode applyng 5v on vbus in two situation
1) otg pin function is activated but nobody is there to drive to true level
2) otg pin function is deactivated and (OPA_MODE=1 & HZ_Mode=0 ) is true
until now ok for me .

a unwanted situation can be achieved when otg pin function is activated and a charger is attached: BQ chip start boost and depending wich source have higher voltage some current flow to other ( vbus > vcharger 200mA flow or vcharger > vbus nothing happen, Bq chip stop injecting power ), disconecting charger will lead to a looked loop BQ chip power the bus and isp chip detect vbus and asserting CHGR_DET sustain boost by BQ chip until battery is exhausted, because otg pin take precedence over i2c, there is no way to stop this situation. some hardware logic missing here.

this can be the reason why nokia not implement host mode ?
there is no need to get vbus from isp chip or twl5030 and all configs of asics seems it can be made by software i think we can get host mode sometimes.

We can check if BQ can drive vbus to 5V by writing an driver and using i2c bus we can activate boost function. anybody already started programming ?

late edit:
don't shoot me joerg_rw ! now, finally, I read what you wrote better. ( non english speaker here )