From: Shuah Khan <shuahkh@osg.samsung.com> To: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>, Mauro Carvalho Chehab <mchehab@osg.samsung.com> Cc: 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, Shuah Khan <shuahkh@osg.samsung.com> Subject: Re: [PATCH 15/31] media: dvb-frontend invoke enable/disable_source handlers Date: Thu, 28 Jan 2016 09:59:38 -0700 [thread overview] Message-ID: <56AA48FA.7070203@osg.samsung.com> (raw) In-Reply-To: <20160128160711.029f3faf@lxorguk.ukuu.org.uk> On 01/28/2016 09:07 AM, One Thousand Gnomes wrote: > 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. Correct. Please check the code. Tuner availability check is done when the device is opened in Write mode in the following conditional. if ((file->f_flags & O_ACCMODE) != O_RDONLY) { >> >> 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. > Returning EBUSY clearly indicates the reason why the device can't be opened in this case. thanks, -- Shuah -- Shuah Khan Sr. Linux Kernel Developer Open Source Innovation Group Samsung Research America (Silicon Valley) shuahkh@osg.samsung.com | (970) 217-8978
WARNING: multiple messages have this Message-ID (diff)
From: Shuah Khan <shuahkh-JPH+aEBZ4P+UEJcrhfAQsw@public.gmane.org> To: One Thousand Gnomes <gnomes-qBU/x9rampVanCEyBjwyrvXRex20P6io@public.gmane.org>, Mauro Carvalho Chehab <mchehab-JPH+aEBZ4P+UEJcrhfAQsw@public.gmane.org> Cc: 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-rMlxZR9MS24@public.gmane.org, joe-amhYAVlgbXj10XsdtD+oqA@public.gmane.org, linuxbugs@vittga Subject: Re: [PATCH 15/31] media: dvb-frontend invoke enable/disable_source handlers Date: Thu, 28 Jan 2016 09:59:38 -0700 [thread overview] Message-ID: <56AA48FA.7070203@osg.samsung.com> (raw) In-Reply-To: <20160128160711.029f3faf-qBU/x9rampVanCEyBjwyrvXRex20P6io@public.gmane.org> On 01/28/2016 09:07 AM, One Thousand Gnomes wrote: > 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. Correct. Please check the code. Tuner availability check is done when the device is opened in Write mode in the following conditional. if ((file->f_flags & O_ACCMODE) != O_RDONLY) { >> >> 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. > Returning EBUSY clearly indicates the reason why the device can't be opened in this case. thanks, -- Shuah -- Shuah Khan Sr. Linux Kernel Developer Open Source Innovation Group Samsung Research America (Silicon Valley) shuahkh-JPH+aEBZ4P+UEJcrhfAQsw@public.gmane.org | (970) 217-8978
next prev parent reply other threads:[~2016-01-28 16:59 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 2016-01-28 16:07 ` One Thousand Gnomes 2016-01-28 16:59 ` Shuah Khan [this message] 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
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=56AA48FA.7070203@osg.samsung.com \ --to=shuahkh@osg.samsung.com \ --cc=alsa-devel@alsa-project.org \ --cc=arnd@arndb.de \ --cc=chehabrafael@gmail.com \ --cc=clemens@ladisch.de \ --cc=corbet@lwn.net \ --cc=crope@iki.fi \ --cc=dan.carpenter@oracle.com \ --cc=daniel@zonque.org \ --cc=dominic.sacre@gmx.de \ --cc=elfring@users.sourceforge.net \ --cc=gnomes@lxorguk.ukuu.org.uk \ --cc=gtmkramer@xs4all.nl \ --cc=hans.verkuil@cisco.com \ --cc=inki.dae@samsung.com \ --cc=javier@osg.samsung.com \ --cc=jh1009.sung@samsung.com \ --cc=joe@oampo.co.uk \ --cc=johan@oljud.se \ --cc=julian@jusst.de \ --cc=k.kozlowski@samsung.com \ --cc=kyungmin.park@samsung.com \ --cc=labbott@fedoraproject.org \ --cc=laurent.pinchart@ideasonboard.com \ --cc=linux-api@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-media@vger.kernel.org \ --cc=linuxbugs@vittgam.net \ --cc=m.szyprowski@samsung.com \ --cc=mchehab@osg.samsung.com \ --cc=misterpib@gmail.com \ --cc=normalperson@yhbt.net \ --cc=p.zabel@pengutronix.de \ --cc=pawel@osciak.com \ --cc=perex@perex.cz \ --cc=pierre-louis.bossart@linux.intel.com \ --cc=prabhakar.csengg@gmail.com \ --cc=ricard.wanderlof@axis.com \ --cc=ricardo.ribalda@gmail.com \ --cc=ruchandani.tina@gmail.com \ --cc=sakari.ailus@linux.intel.com \ --cc=stefanr@s5r6.in-berlin.de \ --cc=sw0312.kim@samsung.com \ --cc=takamichiho@gmail.com \ --cc=tiwai@suse.com \ --cc=tvboxspy@gmail.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.