From: Jiri Kosina <jkosina@suse.cz>
To: "Bruno Prémont" <bonbons@linux-vserver.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
linux-input@vger.kernel.org, linux-usb@vger.kernel.org,
linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org,
"Rick L. Vinyard Jr." <rvinyard@cs.nmsu.edu>,
Nicu Pavel <npavel@ituner.com>, Oliver Neukum <oliver@neukum.org>,
Jaya Kumar <jayakumar.lkml@gmail.com>
Subject: Re: [PATCH v2 1/6] hid: new driver for PicoLCD device
Date: Mon, 22 Mar 2010 08:54:12 +0000 [thread overview]
Message-ID: <alpine.LNX.2.00.1003220951440.18642@pobox.suse.cz> (raw)
In-Reply-To: <20100321173737.5fcf3580@neptune.home>
On Sun, 21 Mar 2010, Bruno Prémont wrote:
> > > + }
> > > + data->status |= PICOLCD_BUSY;
> > > + data->pending = work;
> > > + for (i = k = 0; i < report->maxfield; i++)
> > > + for (j = 0; j < report->field[i]->report_count; j++) {
> > > + hid_set_field(report->field[i], j, k < size ? raw_data[k] : 0);
> > > + k++;
> > > + }
> > > + usbhid_submit_report(data->hdev, report, USB_DIR_OUT);
> > > + complete_all(&data->ready);
> > > + INIT_COMPLETION(data->ready);
> >
> > Umm, what does this do, exactly?
> >
> It wakes up anyone waiting on the completion and then resets the completion
> as otherwise any future attempt to wait on it would succeed immediately.
>
> The complete_all() instead of just complete() comes from the reset() function.
> I can probably reduce it here.
>
> Will check this combined with your mutex suggestion above.
I am afraid this code is racy as is. You can't be sure that whoever has
been waiting on the completion has been notified already between
complete_all() and INIT_COMPLETION(), can you?
Thanks for the driver!
--
Jiri Kosina
SUSE Labs, Novell Inc.
next prev parent reply other threads:[~2010-03-22 8:54 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-20 16:00 [PATCH v2 0/6] hid: new driver for PicoLCD device Bruno Prémont
[not found] ` <20100320170014.440959a8-hY15tx4IgV39zxVx7UNMDg@public.gmane.org>
2010-03-20 16:02 ` [PATCH v2 1/6] " Bruno Prémont
2010-03-21 3:46 ` Dmitry Torokhov
[not found] ` <20100321034600.GE29360-WlK9ik9hQGAhIp7JRqBPierSzoNAToWh@public.gmane.org>
2010-03-21 16:37 ` Bruno Prémont
2010-03-22 4:35 ` Dmitry Torokhov
[not found] ` <20100322043508.GC31621-WlK9ik9hQGAhIp7JRqBPierSzoNAToWh@public.gmane.org>
2010-03-22 11:38 ` Bruno Prémont
2010-03-22 8:54 ` Jiri Kosina [this message]
2010-03-20 16:04 ` [PATCH v2 2/6] hid: add framebuffer support to " Bruno Prémont
2010-03-21 3:25 ` Dmitry Torokhov
2010-03-21 7:24 ` Jaya Kumar
2010-03-21 16:11 ` Bruno Prémont
2010-03-22 8:56 ` Jiri Kosina
2010-03-20 16:06 ` [PATCH v2 3/6] hid: add backlight " Bruno Prémont
2010-03-22 8:59 ` Jiri Kosina
2010-03-22 11:01 ` Bruno Prémont
2010-03-20 16:08 ` [PATCH v2 4/6] hid: add lcd " Bruno Prémont
2010-03-20 16:10 ` [PATCH v2 5/6] hid: add GPO (leds) " Bruno Prémont
2010-03-20 16:11 ` [PATCH v2 6/6] hid: add experimental access to PicoLCD device's Bruno Prémont
2010-03-21 3:08 ` Dmitry Torokhov
[not found] ` <20100321030802.GB29360-WlK9ik9hQGAhIp7JRqBPierSzoNAToWh@public.gmane.org>
2010-03-21 10:29 ` Bruno Prémont
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=alpine.LNX.2.00.1003220951440.18642@pobox.suse.cz \
--to=jkosina@suse.cz \
--cc=bonbons@linux-vserver.org \
--cc=dmitry.torokhov@gmail.com \
--cc=jayakumar.lkml@gmail.com \
--cc=linux-fbdev@vger.kernel.org \
--cc=linux-input@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-usb@vger.kernel.org \
--cc=npavel@ituner.com \
--cc=oliver@neukum.org \
--cc=rvinyard@cs.nmsu.edu \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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).