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Date:      Fri, 3 Jul 2020 11:06:59 +0200
From:      Tomasz CEDRO <tomek@cedro.info>
To:        Hans Petter Selasky <hps@selasky.org>
Cc:        Jan Behrens <jbe-mlist@magnetkern.de>,  "freebsd-usb@FreeBSD.org" <freebsd-usb@freebsd.org>
Subject:   Re: USB reset fails when using a LimeSDR Mini on FreeBSD
Message-ID:  <CAM8r67AKeLUfMqyL3_Ejh_2=LJrM-nCe22c7E3%2BiKLfBncxBRQ@mail.gmail.com>
In-Reply-To: <4fdcdc92-6a0d-5645-0a10-e95d69001d3a@selasky.org>
References:  <20200625121052.e9f7e7cbeb68fad264ec80a9@magnetkern.de> <20200627144419.f14371695d9b62ea99106c4a@magnetkern.de> <CAM8r67DTKdj0%2BhkOegjBj-ywzWFq2CnS2sQed0mibSUeGp6HSQ@mail.gmail.com> <20200627173604.7f7b7777140e66dbad812fc7@magnetkern.de> <CAM8r67DqZzje=JnrT_R3d6Uo_NxjvGsvpydd1NOTrJHU2jHzQA@mail.gmail.com> <20200627180420.4b8012fb@ernst.home> <20200702103523.adb0566bcc7b6e354905a8a5@magnetkern.de> <97c8fd11-9200-dff7-4c68-b0b80cc44871@selasky.org> <20200702104743.223e98c325806025704703f2@magnetkern.de> <e3bd0417-c89c-5598-448e-33ec1e505a3f@selasky.org> <20200702111538.e7edf0ae8d10ec7ede9acebb@magnetkern.de> <9e14575a-5c8b-28c8-6593-22019a21e7e7@selasky.org> <20200702120655.73d1111e2de81c626be78139@magnetkern.de> <8ac365f3-3d33-4730-622e-e66f29dd5938@selasky.org> <20200702123747.1bdf36b9d2ebe283f7bb855e@magnetkern.de> <a6077d0e-71d6-4067-2651-428ce175b33b@selasky.org> <20200703095108.7ce5497f53ed4c4a3d7289e3@magnetkern.de> <4fdcdc92-6a0d-5645-0a10-e95d69001d3a@selasky.org>

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pt., 3 lip 2020, 10:10 u=C5=BCytkownik Hans Petter Selasky napisa=C5=82:

> > I see three possible approaches currently:
> >
> > 1. Allowing a USB reset if the user has access to /dev/ugenX.Y (might
> >     allow users to mess with kernel's operation on a device, unless the
> >     problem exists anyway, see my questions above).
> >
> > 2. Allowing a USB reset if the user has access to /dev/ugenX.Y and
> >     there are other prerequirements fulfilled (e.g. a sysctl setting to
> >     enable it globally, which might not be fine-graded enough, or the
> >     requirement that there is currently no kernel driver attached, or a
> >     combination thereof).
> >
> > 3. Providing a way to grant "reset permissions" on a per-device basis
> >     (might be overkill, and not really needed).
> >
>
> Maybe you're right we should allow this for non-root aswell. I need to
> think about it!
>

+1 for user enabled actions like usb reset and kernel driver detach :-)
maybe based on a sysctl like usermount, i.e. usb_allow_user_device_reset
and usb_allow_user_kernel_driver_detach..?

One would allow user to reset a usb device. This is sometimes required to
restore device or change its configration.

Second would allow user for example to unload ucom driver that is attached
to a device which does not seem possible right now and causes problem with
i.e. pyOCD / some debug probes.

Best regards :-)
Tomek

--
CeDeROM, SQ7MHZ, http://www.tomek.cedro.info



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