Arend van Spriel <arend.vanspriel@xxxxxxxxxxxx> writes: > + Marcel > > On 3/2/2018 6:14 AM, Kalle Valo wrote: >> Arend van Spriel <arend.vanspriel@xxxxxxxxxxxx> writes: >> >>> On 3/1/2018 6:59 PM, Tamizh chelvam wrote: >>>> From: Tamizh chelvam <tamizhr@xxxxxxxxxxxxxx> >>>> >>>> This patch introduces NL80211_CMD_SET_BTCOEX command and >>>> NL80211_ATTR_BTCOEX_OP attribute to enable or disable btcoex. >>> >>> What kind of btcoex are we talking about here? Is it signalling >>> between wlan and bt to get access to the shared RF. >> >> Yes, at least that's how I understand this. >> >>> Why would it require user-space interaction? Are there no options for >>> wlan to detect bt is in use, ie. bt hci is setup, and vice versa. Can >>> it be indicated in platform data or device tree. Trying to understand >>> the use-case here. >> >> One use case is being able to disable btcoex in case of problems or to >> test if it's btcoex related. I think during the last five years the need >> for this interface has come every once in a while. > > Well, you would want to disable btcoex *and* bt to verify wlan is > working properly on its own. And similarly disable btcoex *and* wlan > to verify bt works properly. Sure. But my main motiviation with this is to replace the module parameters we already have: drivers/net/wireless/ath/ath9k/htc_drv_init.c:module_param_named(btcoex_enable, ath9k_htc_btcoex_enable, int, 0444); drivers/net/wireless/ath/ath9k/htc_drv_init.c:MODULE_PARM_DESC(btcoex_enable, "Enable wifi-BT coexistence"); drivers/net/wireless/ath/ath9k/init.c:module_param_named(btcoex_enable, ath9k_btcoex_enable, int, 0444); drivers/net/wireless/ath/ath9k/init.c:MODULE_PARM_DESC(btcoex_enable, "Enable wifi-BT coexistence"); drivers/net/wireless/broadcom/b43/main.c:module_param_named(btcoex, modparam_btcoex, int, 0444); drivers/net/wireless/broadcom/b43/main.c:MODULE_PARM_DESC(btcoex, "Enable Bluetooth coexistence (default on)"); But looking closely in ath9k cases it doesn't actually sound doable as IIRC the ath9k module parameters are off by default. In b43 it's enabled by default, though. > Now I do recall a thread between you and Marcel. Looked it up and it > was this thread [1], but did not see a follow-up on it. I suspect it > involves more than just an enable/disable state. That may be fine for > devices in which BT and WLAN are integrated and coordination of RF use > is done on the device. The "btcoex subsystem" thread seems to aim for > more like providing the coordination logic so independent BT device > and WLAN device can still use the same RF. So before adopting the api > in nl80211 it would be good to revive that thread. I think that "btcoex subsystem" is a holy grail which will be never implemented :) But who knows, miracles can happen... -- Kalle Valo
