Return-Path: Cc: linux-bluetooth@vger.kernel.org Message-Id: <116A4F08-BE16-4AAE-BFFB-5EDAD2C387B6@gmail.com> From: Carles Cufi To: Ilya Rubtsov In-Reply-To: <49C18674.80801@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed; delsp=yes Mime-Version: 1.0 (Apple Message framework v930.3) Subject: Re: Set Tmin and Tmax for inquiry? Date: Thu, 19 Mar 2009 15:07:44 +0100 References: <49C10E12.3030708@gmail.com> <49C15CC3.3010409@gmail.com> <463DDAC5-0E5C-4BD4-B167-F7590A01EADC@gmail.com> <49C18674.80801@gmail.com> Sender: linux-bluetooth-owner@vger.kernel.org List-ID: Hi Ilya, The fact of name resolution being optional has always been a subject of debate. Recently the D-Bus APIs also removed the call for discovery without name resolving. If you want pure inquiry (or periodic inquiry) without names, you can always use the C APIs, which will allow you to do whatever you want with the radio. -- Carles On Mar 19, 2009, at 12:40 AM, Ilya Rubtsov wrote: > Thanks for reply. I have talk to Vudentz at #blues and now know that > both sets of Tmin and Tmax are hardcoded. He also said me that I can > use software scheduler, so I do. > Also he said that API's interval is longer (min 16, max 24) because > there is name resolution feature. > So, I wonder - why this feature is not optional? I think not all > application need name resolution. Another idea (Vudentz's idea) is > to hardcode min 10 to API - if chip is smart it will able to end > work earlier. > > > Carles Cufi пишет: >> Hi Ilya, >> >> The hcitool application uses the HCI library function >> hci_send_req() to send a periodic inquiry request to the >> controller. The max and min periods are hardcoded to 16 and 10 >> respectively, and there is no user option to change those. In the >> case of your python script I can't tell you for sure because I >> haven't looked at the code of the python BlueZ bindings, but if the >> API call it presents to you has no Tmin and Tmax that means it's >> hardcoded there too. The bluetoothd (formerly called hcid) has >> absolutely nothing to do with the hcitool since this tool bypasses >> it completely. For python, you should look at the code for the >> bindings and find out how the API implementation handles your call. >> >> -- >> Carles >> >> On Mar 18, 2009, at 9:42 PM, Ilya Rubtsov wrote: >> >>> Oops. Mistake. Right is: 'max 24 min 16 lap 0x9e8b33 len 8 num >>> 0' (StartDiscovery) and 'max 16 min 10 lap 0x9e8b33 len 8 num >>> 0' (hcitool) >>> >>> Ilya Rubtsov пишет: >>> >>>> Hi >>>> >>>> I'm developing an application for bluecasting. So period of >>>> periodic inquire is important for me. >>>> AFAIK, inquire process takes 10.24 seconds (Bluetooth 2.0). But >>>> if I use StartDiscovery method in python script, then I see this >>>> in hcidump: >>>> >>>> < HCI Command: Periodic Inquiry Mode (0x01|0x0003) plen 9 >>>> max 24 min 16 lap 0x9e8b33 len 8 num 0 >>>> >>>> and I get "Inquiry Complete" event every ~24-30 second. But if I >>>> use 'hcitool spinq', then I see: >>>> >>>> < HCI Command: Periodic Inquiry Mode (0x01|0x0003) plen 9 >>>> max 24 min 16 lap 0x9e8b33 len 8 num 0 >>>> >>>> and "Inquiry Complete" event takes place every ~13-15 seconds. >>>> And in both cases all remote devices is being founded, so I don't >>>> see any reason for longer inquiring. AFAIK HCID internally sets >>>> Tmin and Tmax parameters, but is there any way to affect to its >>>> 'decision'? >>>> >>>> P.S. Excuse me for my English :( >>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux- >>> bluetooth" in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > -- > To unsubscribe from this list: send the line "unsubscribe linux- > bluetooth" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html