Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4

From	One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Newsgroups	linux.kernel
Subject	Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4
Date	2016-01-22 21:20 +0100
Message-ID	<qTQlA-Ac-3@gated-at.bofh.it> (permalink)
References	(13 earlier) <qSqCS-79p-13@gated-at.bofh.it> <qT3Ee-yP-17@gated-at.bofh.it> <qT53k-1s5-17@gated-at.bofh.it> <qT5mG-1Ph-9@gated-at.bofh.it> <qTMhZ-62g-21@gated-at.bofh.it>
Organization	Intel Corporation

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> I would have expected that the main (and IMO sufficient) reason why
> the kernel should do it is because the particular bus used to connect
> a BT chip to the CPU is a hw detail that a kernel that does its job
> should keep to itself. Same as userspace not needing to care if a BT
> chip is behind SDIO or USB, why does it have to tell the kernel behind
> which UART a BT chip is sitting?

Lots of reasons, some historic some not

1. Different BT chips have different interfaces, especially when it gets
to stuff like firmware reprogramming

2. In many cases we don't know at the kernel level where there are BT
uarts. It's improving with recent ACPI but for many systems it's simply
not available to the OS

3. The power management for a lot of BT (especially on device tree) is
not actually expressed, so you need a slightly customised daemon for each
device - that one is ugly but the serial and bt layers can't fix it.

4. Because you don't want to just automatically load and turn on
bluetooth just because it is there - it burns power


There is lots of stuff we probe and bind via user space - most things
these days in fact. That's much of why we have notifiers and udev. It's
frequently a win in flexibility, security and configurability to do stuff
via user daemons. We do it for example with all the volume management,
raid and disk encryption.

Alan

Thread

Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 Mark Rutland <mark.rutland@arm.com> - 2016-01-15 12:10 +0100
  Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-01-15 16:10 +0100
    Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 Andrey Vostrikov <andrey.vostrikov@cogentembedded.com> - 2016-01-15 16:50 +0100
      Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-01-15 17:10 +0100
        Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 Peter Hurley <peter@hurleysoftware.com> - 2016-01-15 18:20 +0100
          Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-01-15 18:40 +0100
            Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 Peter Hurley <peter@hurleysoftware.com> - 2016-01-15 18:50 +0100
              Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-01-15 19:00 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 Peter Hurley <peter@hurleysoftware.com> - 2016-01-15 20:30 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-01-15 22:30 +0100
          Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 Rob Herring <robherring2@gmail.com> - 2016-01-15 23:50 +0100
            Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 Vostrikov Andrey <andrey.vostrikov@cogentembedded.com> - 2016-01-16 08:40 +0100
              Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 Rob Herring <robh@kernel.org> - 2016-01-17 00:40 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-01-17 10:00 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-01-17 15:30 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-01-17 19:00 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-01-17 20:40 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-01-18 09:20 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 Andrey Vostrikov <andrey.vostrikov@cogentembedded.com> - 2016-01-18 10:00 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-01-18 13:00 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-01-18 12:30 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-01-18 22:00 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-01-18 23:10 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-01-18 23:40 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-01-19 15:30 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-01-20 18:40 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-01-20 17:20 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-01-20 18:50 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-01-20 19:10 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 Tomeu Vizoso <tomeu@tomeuvizoso.net> - 2016-01-22 17:00 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 Rob Herring <robherring2@gmail.com> - 2016-01-22 18:00 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-01-22 21:20 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 Andreas Kemnade <andreas@kemnade.info> - 2016-01-23 08:50 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-01-23 13:20 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-01-23 18:30 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-01-23 23:10 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-01-24 18:20 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-01-25 11:40 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 Andreas Kemnade <andreas@kemnade.info> - 2016-01-19 07:40 +0100
              Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2016-01-20 20:40 +0100
                Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 Vostrikov Andrey <andrey.vostrikov@cogentembedded.com> - 2016-01-20 21:10 +0100
    Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 Mark Rutland <mark.rutland@arm.com> - 2016-01-15 17:20 +0100
      Re: [Gta04-owner] [PATCH 0/4] UART slave device support - version 4 "H. Nikolaus Schaller" <hns@goldelico.com> - 2016-01-15 20:20 +0100

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