From: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
To: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>,
tiwai@suse.com, clemens@ladisch.de, hans.verkuil@cisco.com,
laurent.pinchart@ideasonboard.com, sakari.ailus@linux.intel.com,
javier@osg.samsung.com, pawel@osciak.com,
m.szyprowski@samsung.com, kyungmin.park@samsung.com,
perex@perex.cz, arnd@arndb.de, dan.carpenter@oracle.com,
tvboxspy@gmail.com, crope@iki.fi, ruchandani.tina@gmail.com,
corbet@lwn.net, chehabrafael@gmail.com, k.kozlowski@samsung.com,
stefanr@s5r6.in-berlin.de, inki.dae@samsung.com,
jh1009.sung@samsung.com, elfring@users.sourceforge.net,
prabhakar.csengg@gmail.com, sw0312.kim@samsung.com,
p.zabel@pengutronix.de, ricardo.ribalda@gmail.com,
labbott@fedoraproject.org, pierre-louis.bossart@linux.intel.com,
ricard.wanderlof@axis.com, julian@jusst.de,
takamichiho@gmail.com, dominic.sacre@gmx.de, misterpib@gmail.com,
daniel@zonque.org, gtmkramer@xs4all.nl, normalperson@yhbt.net,
joe@oampo.co.uk, linuxbugs@vittgam.net, johan@oljud.se,
linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
linux-api@vger.kernel.org, alsa-devel@alsa-project.org
Subject: Re: [PATCH 15/31] media: dvb-frontend invoke enable/disable_source handlers
Date: Thu, 28 Jan 2016 16:07:11 +0000 [thread overview]
Message-ID: <20160128160711.029f3faf@lxorguk.ukuu.org.uk> (raw)
In-Reply-To: <20160128135304.3daa79f1@recife.lan>
On Thu, 28 Jan 2016 13:53:04 -0200
Mauro Carvalho Chehab <mchehab@osg.samsung.com> wrote:
> Em Wed, 6 Jan 2016 13:27:04 -0700
> Shuah Khan <shuahkh@osg.samsung.com> escreveu:
>
> > Checking for tuner availability from frontend thread start
> > disrupts video stream. Change to check for tuner and start
> > pipeline from frontend open instead and stop pipeline from
> > frontend release.
>
> That's wrong, as DVB can be opened on read-only mode, where
> it won't be changing anything.
>
> Also, I don't think POSIX allows to return an error like EBUSY
> on open:
> http://pubs.opengroup.org/onlinepubs/9699919799/functions/open.html
It doesn't document all the errors you may return. Quite a lot of
kernel drivers return EBUSY when they are "single open" things.
POSIX documents certain cases that *must* error and what the error code
is. It documents certain possible failures and what their error code is.
Beyond that it's up to you.
Alan
WARNING: multiple messages have this Message-ID (diff)
From: One Thousand Gnomes <gnomes-qBU/x9rampVanCEyBjwyrvXRex20P6io@public.gmane.org>
To: Mauro Carvalho Chehab <mchehab-JPH+aEBZ4P+UEJcrhfAQsw@public.gmane.org>
Cc: Shuah Khan <shuahkh-JPH+aEBZ4P+UEJcrhfAQsw@public.gmane.org>,
tiwai-IBi9RG/b67k@public.gmane.org,
clemens-P6GI/4k7KOmELgA04lAiVw@public.gmane.org,
hans.verkuil-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org,
laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org,
sakari.ailus-VuQAYsv1563Yd54FQh9/CA@public.gmane.org,
javier-JPH+aEBZ4P+UEJcrhfAQsw@public.gmane.org,
pawel-FA/gS7QP4orQT0dZR+AlfA@public.gmane.org,
m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org,
kyungmin.park-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org,
perex-/Fr2/VpizcU@public.gmane.org,
arnd-r2nGTMty4D4@public.gmane.org,
dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org,
tvboxspy-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
crope-X3B1VOXEql0@public.gmane.org,
ruchandani.tina-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
corbet-T1hC0tSOHrs@public.gmane.org,
chehabrafael-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
k.kozlowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org,
stefanr-MtYdepGKPcBMYopoZt5u/LNAH6kLmebB@public.gmane.org,
inki.dae-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org,
jh1009.sung-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org,
elfring-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
prabhakar.csengg-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
sw0312.kim-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org,
p.zabel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org,
ricardo.ribalda-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
labbott-rxtnV0ftBwyoClj4AeEUq9i2O/JbrIOy@public.gmane.org,
pierre-louis.bossart-VuQAYsv1563Yd54FQh9/CA@public.gmane.org,
ricard.wanderlof-VrBV9hrLPhE@public.gmane.org,
julian-SZMMDGyaqes@public.gmane.org,
takamichiho-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
dominic.sacre-Mmb7MZpHnFY@public.gmane.org,
misterpib-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
daniel-cYrQPVfZoowdnm+yROfE0A@public.gmane.org,
gtmkramer-qWit8jRvyhVmR6Xm/wNWPw@public.gmane.org,
normalperson@yhbt
Subject: Re: [PATCH 15/31] media: dvb-frontend invoke enable/disable_source handlers
Date: Thu, 28 Jan 2016 16:07:11 +0000 [thread overview]
Message-ID: <20160128160711.029f3faf@lxorguk.ukuu.org.uk> (raw)
In-Reply-To: <20160128135304.3daa79f1-+RedX5hVuTR+urZeOPWqwQ@public.gmane.org>
On Thu, 28 Jan 2016 13:53:04 -0200
Mauro Carvalho Chehab <mchehab-JPH+aEBZ4P+UEJcrhfAQsw@public.gmane.org> wrote:
> Em Wed, 6 Jan 2016 13:27:04 -0700
> Shuah Khan <shuahkh-JPH+aEBZ4P+UEJcrhfAQsw@public.gmane.org> escreveu:
>
> > Checking for tuner availability from frontend thread start
> > disrupts video stream. Change to check for tuner and start
> > pipeline from frontend open instead and stop pipeline from
> > frontend release.
>
> That's wrong, as DVB can be opened on read-only mode, where
> it won't be changing anything.
>
> Also, I don't think POSIX allows to return an error like EBUSY
> on open:
> http://pubs.opengroup.org/onlinepubs/9699919799/functions/open.html
It doesn't document all the errors you may return. Quite a lot of
kernel drivers return EBUSY when they are "single open" things.
POSIX documents certain cases that *must* error and what the error code
is. It documents certain possible failures and what their error code is.
Beyond that it's up to you.
Alan
next prev parent reply other threads:[~2016-01-28 16:09 UTC|newest]
Thread overview: 157+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-06 20:26 [PATCH 00/31] Sharing media resources across ALSA and au0828 drivers Shuah Khan
2016-01-06 20:26 ` Shuah Khan
2016-01-06 20:26 ` [PATCH 01/31] uapi/media.h: Declare interface types for ALSA Shuah Khan
2016-01-28 14:59 ` Mauro Carvalho Chehab
2016-01-28 14:59 ` Mauro Carvalho Chehab
2016-02-01 16:07 ` Shuah Khan
2016-02-01 16:07 ` Shuah Khan
2016-02-01 16:18 ` Takashi Iwai
2016-02-01 16:18 ` Takashi Iwai
2016-02-01 17:04 ` Shuah Khan
2016-02-01 17:04 ` Shuah Khan
2016-01-06 20:26 ` [PATCH 02/31] media: Add ALSA Media Controller function entities Shuah Khan
2016-01-06 20:26 ` Shuah Khan
2016-01-28 15:02 ` Mauro Carvalho Chehab
2016-01-28 15:02 ` Mauro Carvalho Chehab
2016-01-06 20:26 ` [PATCH 03/31] media: Media Controller register/unregister entity_notify API Shuah Khan
2016-01-06 20:26 ` Shuah Khan
2016-01-28 15:13 ` Mauro Carvalho Chehab
2016-01-28 15:13 ` Mauro Carvalho Chehab
2016-01-28 17:09 ` Shuah Khan
2016-01-28 17:09 ` Shuah Khan
2016-01-06 20:26 ` [PATCH 04/31] media: Media Controller enable/disable source handler API Shuah Khan
2016-01-06 20:26 ` Shuah Khan
2016-01-28 15:19 ` Mauro Carvalho Chehab
2016-01-28 15:19 ` Mauro Carvalho Chehab
2016-01-28 16:28 ` Shuah Khan
2016-01-28 16:28 ` Shuah Khan
2016-01-28 17:15 ` Mauro Carvalho Chehab
2016-01-28 17:15 ` Mauro Carvalho Chehab
2016-01-28 20:33 ` Shuah Khan
2016-01-28 20:33 ` Shuah Khan
2016-01-06 20:26 ` [PATCH 05/31] media: Media Controller fix to not let stream_count go negative Shuah Khan
2016-01-06 20:26 ` Shuah Khan
2016-01-06 20:26 ` [PATCH 06/31] media: Media Controller export non locking __media_entity_setup_link() Shuah Khan
2016-01-06 20:26 ` Shuah Khan
2016-01-06 20:26 ` [PATCH 07/31] media: Media Controller non-locking __media_entity_pipeline_start/stop() Shuah Khan
2016-01-06 20:26 ` Shuah Khan
2016-01-06 20:26 ` [PATCH 08/31] media: v4l-core add v4l_enable/disable_media_tuner() helper functions Shuah Khan
2016-01-06 20:26 ` Shuah Khan
2016-01-28 15:26 ` Mauro Carvalho Chehab
2016-01-28 15:26 ` Mauro Carvalho Chehab
2016-01-28 17:12 ` Shuah Khan
2016-01-28 17:12 ` Shuah Khan
2016-01-06 20:26 ` [PATCH 09/31] media: v4l2-core add v4l_vb2q_enable_media_tuner() helper Shuah Khan
2016-01-06 20:26 ` Shuah Khan
2016-01-28 15:29 ` Mauro Carvalho Chehab
2016-01-28 15:29 ` Mauro Carvalho Chehab
2016-01-28 17:31 ` Shuah Khan
2016-01-28 17:31 ` Shuah Khan
2016-01-28 17:34 ` Mauro Carvalho Chehab
2016-01-28 17:34 ` Mauro Carvalho Chehab
2016-01-06 20:26 ` [PATCH 10/31] media: Move au8522_media_pads enum to au8522.h from au8522_priv.h Shuah Khan
2016-01-06 20:26 ` Shuah Khan
2016-01-06 20:27 ` [PATCH 11/31] media: au8522 change to create MC pad for ALSA Audio Out Shuah Khan
2016-01-06 20:27 ` Shuah Khan
2016-01-06 20:27 ` [PATCH 12/31] media: au0828 Use au8522_media_pads enum for pad defines Shuah Khan
2016-01-06 20:27 ` Shuah Khan
2016-01-06 20:27 ` [PATCH 13/31] media: au0828 fix au0828_create_media_graph() entity checks Shuah Khan
2016-01-06 20:27 ` Shuah Khan
2016-01-28 15:37 ` Mauro Carvalho Chehab
2016-01-28 15:37 ` Mauro Carvalho Chehab
2016-01-28 18:57 ` Shuah Khan
2016-01-28 18:57 ` Shuah Khan
2016-01-06 20:27 ` [PATCH 14/31] media: Change v4l-core to check for tuner availability Shuah Khan
2016-01-06 20:27 ` Shuah Khan
2016-01-06 20:27 ` [PATCH 15/31] media: dvb-frontend invoke enable/disable_source handlers Shuah Khan
2016-01-06 20:27 ` Shuah Khan
2016-01-28 15:53 ` Mauro Carvalho Chehab
2016-01-28 15:53 ` Mauro Carvalho Chehab
2016-01-28 16:07 ` One Thousand Gnomes [this message]
2016-01-28 16:07 ` One Thousand Gnomes
2016-01-28 16:59 ` Shuah Khan
2016-01-28 16:59 ` Shuah Khan
2016-01-28 17:31 ` Mauro Carvalho Chehab
2016-01-28 17:31 ` Mauro Carvalho Chehab
2016-01-06 20:27 ` [PATCH 16/31] media: au0828 video remove au0828_enable_analog_tuner() Shuah Khan
2016-01-06 20:27 ` Shuah Khan
2016-01-06 20:27 ` [PATCH 17/31] media: au0828 video change to use v4l_enable_media_tuner() Shuah Khan
2016-01-06 20:27 ` Shuah Khan
2016-01-28 15:57 ` Mauro Carvalho Chehab
2016-01-28 15:57 ` Mauro Carvalho Chehab
2016-01-28 19:21 ` Shuah Khan
2016-01-28 19:21 ` Shuah Khan
2016-01-28 19:33 ` Devin Heitmueller
2016-01-28 19:33 ` Devin Heitmueller
2016-01-06 20:27 ` [PATCH 18/31] media: au0828 change to use Managed Media Controller API Shuah Khan
2016-01-06 20:27 ` Shuah Khan
2016-01-06 20:27 ` [PATCH 19/31] media: au0828 handle media_init and media_register window Shuah Khan
2016-01-06 20:27 ` Shuah Khan
2016-01-06 20:27 ` [PATCH 20/31] media: au0828 change to register/unregister entity_notify hook Shuah Khan
2016-01-06 20:27 ` Shuah Khan
2016-01-28 16:36 ` Mauro Carvalho Chehab
2016-01-28 16:36 ` Mauro Carvalho Chehab
2016-01-28 20:05 ` Shuah Khan
2016-01-28 20:05 ` Shuah Khan
2016-01-28 20:20 ` Mauro Carvalho Chehab
2016-01-28 20:20 ` Mauro Carvalho Chehab
2016-01-06 20:27 ` [PATCH 21/31] media: au0828 create tuner to decoder link in deactivated state Shuah Khan
2016-01-06 20:27 ` Shuah Khan
2016-01-06 20:27 ` [PATCH 22/31] media: dvb-core create tuner to demod pad link in disabled state Shuah Khan
2016-01-06 20:27 ` Shuah Khan
2016-01-28 16:38 ` Mauro Carvalho Chehab
2016-01-28 16:38 ` Mauro Carvalho Chehab
2016-01-28 20:09 ` Shuah Khan
2016-01-28 20:09 ` Shuah Khan
2016-01-06 20:27 ` [PATCH 23/31] media: au0828 implement enable_source and disable_source handlers Shuah Khan
2016-01-06 20:27 ` Shuah Khan
2016-01-28 16:43 ` Mauro Carvalho Chehab
2016-01-28 16:43 ` Mauro Carvalho Chehab
2016-01-28 20:14 ` Shuah Khan
2016-01-28 20:14 ` Shuah Khan
2016-01-06 20:27 ` [PATCH 24/31] media: au0828 fix null pointer reference in au0828_create_media_graph() Shuah Khan
2016-01-06 20:27 ` Shuah Khan
2016-01-28 16:44 ` Mauro Carvalho Chehab
2016-01-28 16:44 ` Mauro Carvalho Chehab
2016-01-28 20:15 ` Shuah Khan
2016-01-28 20:15 ` Shuah Khan
2016-01-06 20:27 ` [PATCH 28/31] media: au0828 create link between ALSA Mixer and decoder Shuah Khan
2016-01-06 20:27 ` Shuah Khan
2016-01-28 16:58 ` Mauro Carvalho Chehab
2016-01-28 16:58 ` Mauro Carvalho Chehab
2016-01-28 20:17 ` Shuah Khan
2016-01-28 20:17 ` Shuah Khan
2016-01-06 20:27 ` [PATCH 29/31] media: track media device unregister in progress Shuah Khan
2016-01-06 20:27 ` Shuah Khan
2016-01-28 17:01 ` Mauro Carvalho Chehab
2016-01-28 17:01 ` Mauro Carvalho Chehab
2016-01-28 17:04 ` Shuah Khan
2016-01-28 17:04 ` Shuah Khan
2016-01-28 17:28 ` Mauro Carvalho Chehab
2016-01-28 17:28 ` Mauro Carvalho Chehab
2016-01-28 20:42 ` Shuah Khan
2016-01-28 20:42 ` Shuah Khan
2016-02-03 19:32 ` Shuah Khan
2016-02-03 19:32 ` Shuah Khan
2016-01-06 20:27 ` [PATCH 30/31] sound/usb: Check media device unregister progress state Shuah Khan
2016-01-06 20:27 ` Shuah Khan
2016-01-06 20:27 ` [PATCH 31/31] media: au0828 change to check " Shuah Khan
2016-01-06 20:27 ` Shuah Khan
2016-01-28 17:05 ` Mauro Carvalho Chehab
2016-01-28 17:05 ` Mauro Carvalho Chehab
2016-01-28 20:31 ` Shuah Khan
2016-01-28 20:31 ` Shuah Khan
2016-01-06 21:01 ` [PATCH 25/31] media: au0828 fix to not call media_device_unregister_entity_notify() Shuah Khan
2016-01-06 21:01 ` Shuah Khan
2016-01-28 16:45 ` Mauro Carvalho Chehab
2016-01-28 16:45 ` Mauro Carvalho Chehab
2016-01-28 20:15 ` Shuah Khan
2016-01-28 20:15 ` Shuah Khan
2016-01-06 21:05 ` [PATCH 26/31] sound/usb: Update ALSA driver to use Managed Media Controller API Shuah Khan
2016-01-06 21:05 ` Shuah Khan
2016-01-07 15:44 ` Takashi Iwai
2016-01-07 15:44 ` Takashi Iwai
2016-01-07 20:27 ` Shuah Khan
2016-01-07 20:27 ` Shuah Khan
2016-01-06 21:05 ` [PATCH 27/31] sound/usb: Create media mixer function and control interface entities Shuah Khan
2016-01-06 21:05 ` Shuah Khan
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