Return-Path: From: "Ziv, Dotan" To: Marcel Holtmann , "Reizer, Eyal" CC: One Thousand Gnomes , Eyal Reizer , "linux-kernel@vger.kernel.org" , Pavan Savoy , "Mahaveer, Vishal" , "linux-bluetooth@vger.kernel.org" Subject: RE: [PATCH] Bluetooth: Add tty HCI driver Date: Thu, 30 Apr 2015 15:08:34 +0000 Message-ID: References: <1430380089-2395-1-git-send-email-eyalr@ti.com> <20150430113103.3ad0bfac@lxorguk.ukuu.org.uk> <2A731A0F-6BEB-4614-94E8-90B28BEE2DD9@holtmann.org> <8665E2433BC68541A24DFFCA87B70F5B2365DFEB@DFRE01.ent.ti.com> In-Reply-To: Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 List-ID: Hi Marcel >-----Original Message----- >From: Marcel Holtmann [mailto:marcel@holtmann.org] >Sent: Thursday, April 30, 2015 5:58 PM >To: Reizer, Eyal >Cc: One Thousand Gnomes; Eyal Reizer; linux-kernel@vger.kernel.org; Pavan >Savoy; Mahaveer, Vishal; linux-bluetooth@vger.kernel.org; Ziv, Dotan >Subject: Re: [PATCH] Bluetooth: Add tty HCI driver > >Hi Eyal, > >>>>> tty_hci driver exposes a /dev/hci_tty character device node, that >>>>> intends to emulate a generic /dev/ttyX device that would be used by >>>>> the user-space Bluetooth stacks to send/receive data to/from the WL >>>>> combo-connectivity chipsets. >>>> >>>> We have an in kernel bluetooth stack, why do we care about this - >>>> how will people test and debug driver interactions with binary only >>>> bluetooth stacks in userspace ? >>> >>> NAK to this driver. >>> >>> If you want to run an external Bluetooth stack, then use HCI User >>> Channel. The functionality already exists. >> >> This is a pretty old driver that has been written a couple of years back= and is >being used by customers (including android that use a userspace based stac= k). >> If there is another driver already available that provides same function= ality, >of course we will be happy to use it instead. >> Any idea of where we can get info on the HCI User Channel? > >search for my BlueZ for Android presentation from Android Builders Summit >from 2014. It has an explanation on how HCI User Channel works. > >Otherwise look into bluez.git since it contains a bunch of examples on how= to >use the HCI User Channel. It is a generic functionality for raw access to = the HCI >layer. Look for HCI_CHANNEL_USER. > >>> We do not want to have two drivers for the same hardware. Work with >>> the Bluetooth stack that is present in the kernel and please stop hacki= ng >around it. >>> >> There are in fact quite a few products that use commercial user space ba= sed >Bluetooth stacks. >> One reason is that bluez has not been certified but I assume they have >other reasons as well. > >Please stop this FUD. BlueZ has been qualified multiple times. > >And let me tell you this, when doing BlueZ for Android, we went through a >lengthy period of qualification and fixing PTS with 65 errata today. I don= 't >know if any commercial stack was actually such a good citizen in ensuring = that >the certification tools get fixed. And we documented all of it. > No argue here, as a matter of fact, we (TI) certified BlueZ several times i= n the past. Our customers are using large variety of Kernel versions and mi= ght use a different version of BlueZ. Our BQE requested us to certify the s= tack per kernel and per BlueZ version which is practically impossible (due = to certification costs and the time it takes).=20 If you are familiar with a way to bypass it, that would be great. >Clone the bluez.git tree and look for android/{pts,pics,pixit}-*.txt files= . They >contain all details for qualifying BlueZ for Android stack. > >Regards > >Marcel Regards, Dotan