LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Andy Walls <awalls@md.metrocast.net>
To: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
	stoth@kernellabs.com
Subject: cx23885-input.c does in fact use a workqueue....
Date: Sun, 13 Feb 2011 20:35:22 -0500	[thread overview]
Message-ID: <1297647322.19186.61.camel@localhost> (raw)

Tejun,

I just noticed this commit:

commit 8c71778cbf2c8beaefaa2dee5478aa0622d96682
Author: Tejun Heo <tj@kernel.org>
Date:   Fri Dec 24 16:14:20 2010 +0100

    media/video: don't use flush_scheduled_work()
    
    This patch converts the remaining users of flush_scheduled_work() in
    media/video.
    
    * bttv-input.c and cx23885-input.c don't use workqueue at all.  No
      need to flush.
[...]


The cx23885 driver does in fact schedule work for IR input handling:

Here's where it is scheduled for CX23888 chips:

http://git.linuxtv.org/media_tree.git?a=blob;f=drivers/media/video/cx23885/cx23885-ir.c;h=7125247dd25558678c823ee3262675570c9aa630;hb=HEAD#l76

Here's where it is scheduled for CX23885 chips:

http://git.linuxtv.org/media_tree.git?a=blob;f=drivers/media/video/cx23885/cx23885-core.c;h=359882419b7f588b7c698dbcfb6a39ddb1603301;hb=HEAD#l1861


The two different chips are handled slightly differently because

a. the CX23888 IR unit is accessable via a PCI register block.  The IR
IRQ can be acknowledged with direct PCI register accesses in an
interrupt context, and the IR pulse FIFO serviced later in a workqueue
context.

b. the CX23885 IR unit is accessed over an I2C bus.  The CX23885 A/V IRQ
has to be masked in an interrupt context (with PCI registers accesses).
Then the CX23885 A/V unit's IR IRQ is ack'ed over I2C in a workqueue
context and the IR pulse FIFO is also serviced over I2C in a workqueue
context.


So what should be done about the flush_scheduled_work()?  I think it
belongs there.

Regards,
Andy


             reply	other threads:[~2011-02-14  1:35 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-14  1:35 Andy Walls [this message]
2011-02-14  4:33 ` Dmitry Torokhov
2011-02-14 11:03   ` Tejun Heo
2011-02-15  0:54     ` Andy Walls
2011-02-15  9:12       ` Tejun Heo
2011-02-15  9:20       ` [PATCH] cx23885: restore flushes of cx23885_dev work items Tejun Heo
2011-02-15 20:00         ` Mauro Carvalho Chehab

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=1297647322.19186.61.camel@localhost \
    --to=awalls@md.metrocast.net \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-media@vger.kernel.org \
    --cc=stoth@kernellabs.com \
    --cc=tj@kernel.org \
    --subject='Re: cx23885-input.c does in fact use a workqueue....' \
    /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: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).