From: Mauro Carvalho Chehab <mchehab@s-opensource.com>
To: Hans Verkuil <hverkuil@xs4all.nl>
Cc: Sakari Ailus <sakari.ailus@iki.fi>,
Sakari Ailus <sakari.ailus@linux.intel.com>,
linux-media@vger.kernel.org, niklas.soderlund@ragnatech.se,
maxime.ripard@free-electrons.com,
laurent.pinchart@ideasonboard.com, pavel@ucw.cz, sre@kernel.org
Subject: Re: [PATCH v15 01/32] v4l: async: Remove re-probing support
Date: Mon, 9 Oct 2017 12:27:42 -0300 [thread overview]
Message-ID: <20171009122742.6b9d82f2@vento.lan> (raw)
In-Reply-To: <e45a2974-2a63-7dca-ca09-fa12532d5325@xs4all.nl>
Em Mon, 9 Oct 2017 16:20:08 +0200
Hans Verkuil <hverkuil@xs4all.nl> escreveu:
> On 09/10/17 16:18, Sakari Ailus wrote:
> > Hi Hans,
> >
> > On Mon, Oct 09, 2017 at 04:08:47PM +0200, Hans Verkuil wrote:
> >> On 09/10/17 16:06, Sakari Ailus wrote:
> >>> Hi Mauro,
> >>>
> >>> On Mon, Oct 09, 2017 at 08:22:39AM -0300, Mauro Carvalho Chehab wrote:
> >>>> Em Thu, 5 Oct 2017 00:50:20 +0300
> >>>> Sakari Ailus <sakari.ailus@linux.intel.com> escreveu:
> >>>>
> >>>>> Remove V4L2 async re-probing support. The re-probing support has been
> >>>>> there to support cases where the sub-devices require resources provided by
> >>>>> the main driver's hardware to function, such as clocks.
> >>>>>
> >>>>> Reprobing has allowed unbinding and again binding the main driver without
> >>>>> explicilty unbinding the sub-device drivers. This is certainly not a
> >>>>> common need, and the responsibility will be the user's going forward.
> >>>>>
> >>>>> An alternative could have been to introduce notifier specific locks.
> >>>>> Considering the complexity of the re-probing and that it isn't really a
> >>>>> solution to a problem but a workaround, remove re-probing instead.
> >>>>
> >>>> If the re-probing isn't using anywhere, that sounds a nice cleanup.
> >>>> Did you check if this won't break any driver (like soc_camera)?
> >>>
> >>> That was discussed earlier in the review; Laurent asked the same question.
> >>>
> >>> Re-probing never was a proper solution to any problem; it was just a hack
> >>> to avoid unbinding the sensor if the bridge driver was unbound, no more: it
> >>> can't be generalised to support more complex use cases. Mind you, this is
> >>> on devices that aren't actually removable.
> >>>
> >>> I've briefly discussed this with Laurent; the proper solution would need to
> >>> be implemented in the clock framework instead. There, the existing clocks
> >>> obtained by drivers could be re-activated when the driver for them comes
> >>> back.
> >>>
> >>> My proposal is that if there's real a need to address this, then it could
> >>> be solved in the clock framework.
> >>
> >> Can you add this information to the commit log?
> >>
> >> I think that would be very helpful in the future.
> >
> > Sure, how about this at the end of the current commit message:
> >
> > If there is a need to support removing the clock provider in the future,
> > this should be implemented in the clock framework instead, not in V4L2.
>
> Yes, that sounds good.
Works for me too.
Regards,
Mauro
next prev parent reply other threads:[~2017-10-09 15:27 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-04 21:50 [PATCH v15 00/32] Unified fwnode endpoint parser, async sub-device notifier support, N9 flash DTS Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 01/32] v4l: async: Remove re-probing support Sakari Ailus
2017-10-08 21:50 ` Sebastian Reichel
2017-10-09 11:22 ` Mauro Carvalho Chehab
2017-10-09 14:06 ` Sakari Ailus
2017-10-09 14:08 ` Hans Verkuil
2017-10-09 14:18 ` Sakari Ailus
2017-10-09 14:20 ` Hans Verkuil
2017-10-09 15:27 ` Mauro Carvalho Chehab [this message]
[not found] ` <CGME20171009164457epcas1p3c5e134e4bb5d85498fe8d4f00332f2fc@epcas1p3.samsung.com>
2017-10-09 16:44 ` Sylwester Nawrocki
2017-10-09 19:18 ` Laurent Pinchart
2017-10-10 12:18 ` Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 02/32] v4l: async: Don't set sd->dev NULL in v4l2_async_cleanup Sakari Ailus
2017-10-08 21:50 ` Sebastian Reichel
2017-10-09 11:21 ` Hans Verkuil
2017-10-04 21:50 ` [PATCH v15 03/32] v4l: async: fix unbind error in v4l2_async_notifier_unregister() Sakari Ailus
2017-10-08 21:50 ` Sebastian Reichel
2017-10-09 11:23 ` Hans Verkuil
2017-10-04 21:50 ` [PATCH v15 04/32] v4l: async: Fix notifier complete callback error handling Sakari Ailus
2017-10-09 11:45 ` Hans Verkuil
2017-10-10 12:57 ` Sakari Ailus
2017-10-10 13:18 ` Hans Verkuil
2017-10-10 14:21 ` Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 05/32] v4l: async: Correctly serialise async sub-device unregistration Sakari Ailus
2017-10-08 21:52 ` Sebastian Reichel
2017-10-09 11:45 ` Hans Verkuil
2017-10-04 21:50 ` [PATCH v15 06/32] v4l: async: Use more intuitive names for internal functions Sakari Ailus
2017-10-08 21:53 ` Sebastian Reichel
2017-10-04 21:50 ` [PATCH v15 07/32] v4l: async: Add V4L2 async documentation to the documentation build Sakari Ailus
2017-10-08 21:54 ` Sebastian Reichel
2017-10-09 11:31 ` Mauro Carvalho Chehab
2017-10-04 21:50 ` [PATCH v15 08/32] v4l: fwnode: Support generic parsing of graph endpoints in a device Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 09/32] omap3isp: Use generic parser for parsing fwnode endpoints Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 10/32] rcar-vin: " Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 11/32] omap3isp: Fix check for our own sub-devices Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 12/32] omap3isp: Print the name of the entity where no source pads could be found Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 13/32] v4l: async: Move async subdev notifier operations to a separate structure Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 14/32] v4l: async: Introduce helpers for calling async ops callbacks Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 15/32] v4l: async: Register sub-devices before calling bound callback Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 16/32] v4l: async: Allow async notifier register call succeed with no subdevs Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 17/32] v4l: async: Prepare for async sub-device notifiers Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 18/32] v4l: async: Allow binding notifiers to sub-devices Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 19/32] v4l: async: Ensure only unique fwnodes are registered to notifiers Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 20/32] dt: bindings: Add a binding for flash LED devices associated to a sensor Sakari Ailus
2017-10-13 13:41 ` Rob Herring
2017-10-04 21:50 ` [PATCH v15 21/32] dt: bindings: Add lens-focus binding for image sensors Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 22/32] v4l: fwnode: Move KernelDoc documentation to the header Sakari Ailus
2017-10-05 12:03 ` [PATCH v15.1 " Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 23/32] v4l: fwnode: Add a helper function for parsing generic references Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 24/32] v4l: fwnode: Add a helper function to obtain device / integer references Sakari Ailus
2017-10-18 13:56 ` [PATCH v15.1 " Sakari Ailus
2017-10-18 15:32 ` Sakari Ailus
2017-10-19 6:52 ` Hans Verkuil
2017-10-20 11:35 ` Sakari Ailus
2017-10-24 20:32 ` [PATCH v15.2 " Sakari Ailus
2017-10-24 20:36 ` Sakari Ailus
2017-10-25 7:28 ` Hans Verkuil
2017-10-04 21:50 ` [PATCH v15 25/32] v4l: fwnode: Add convenience function for parsing common external refs Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 26/32] v4l: fwnode: Add a convenience function for registering sensors Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 27/32] dt: bindings: smiapp: Document lens-focus and flash-leds properties Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 28/32] smiapp: Add support for flash and lens devices Sakari Ailus
2017-10-06 11:21 ` Pavel Machek
2017-10-04 21:50 ` [PATCH v15 29/32] et8ek8: " Sakari Ailus
2017-10-06 11:21 ` Pavel Machek
2017-10-04 21:50 ` [PATCH v15 30/32] ov5670: " Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 31/32] ov13858: " Sakari Ailus
2017-10-04 21:50 ` [PATCH v15 32/32] arm: dts: omap3: N9/N950: Add flash references to the camera Sakari Ailus
2017-10-05 6:11 ` [PATCH v15 00/32] Unified fwnode endpoint parser, async sub-device notifier support, N9 flash DTS Sakari Ailus
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