From: Bart Hartgers <bart.hartgers@gmail.com>
To: Oliver Neukum <oliver@neukum.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/7] ark3116: (3rd try) Replace cmget
Date: Sun, 25 Oct 2009 20:56:36 +0100 [thread overview]
Message-ID: <7eb6a4d80910251256w4ad8a77dg5a24618657b77a58@mail.gmail.com> (raw)
In-Reply-To: <200910252052.09845.oliver@neukum.org>
2009/10/25 Oliver Neukum <oliver@neukum.org>:
> Am Sonntag, 25. Oktober 2009 18:51:00 schrieb bart.hartgers@gmail.com:
>> + /* read modem status */
>> + unsigned status = atomic_read(&priv->msr);
>> + /* modem control is output */
>> + unsigned ctrl = atomic_read(&priv->mcr);
>
> What is the sense of having two atomic variables?
> You can get races where one is changed but the other is not.
>
> Regards
> Oliver
>
>
Hi Oliver,
I don't think so. The two values are not really related.
These are two separate things: mcr (modem control reg) is ultimately
changed by whatever has the serial port open, msr (modem status
register) represents the status of the handshaking lines, and is
changed (via the interrupt urb callback) by hardware.
Groeten,
Bart
--
Bart Hartgers - New e-mail: bart.hartgers@gmail.com
next prev parent reply other threads:[~2009-10-25 19:56 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-25 17:50 [PATCH 0/7] ark3116: (3rd try) driver rework bart.hartgers
2009-10-25 17:50 ` [PATCH 1/7] ark3116: (3rd try) Setup some basic infrastructure for new ark3116 driver bart.hartgers
2009-10-27 17:46 ` Greg KH
2009-10-27 21:35 ` Bart Hartgers
2009-10-27 22:11 ` Greg KH
2009-10-25 17:50 ` [PATCH 2/7] ark3116: (3rd try) Make existing functions 16450-aware and add close and release functions bart.hartgers
2009-10-25 19:56 ` Oliver Neukum
2009-10-25 17:51 ` [PATCH 3/7] ark3116: (3rd try) Replace cmget bart.hartgers
2009-10-25 19:52 ` Oliver Neukum
2009-10-25 19:56 ` Bart Hartgers [this message]
2009-10-25 22:08 ` Oliver Neukum
2009-10-25 17:51 ` [PATCH 4/7] ark3116: (3rd try) Add atomic set-and-clear function bart.hartgers
2009-10-25 17:51 ` [PATCH 5/7] ark3116: (3rd try) Add cmset and break bart.hartgers
2009-10-25 17:51 ` [PATCH 6/7] ark3116: (3rd try) Callbacks for interrupt and bulk read bart.hartgers
2009-10-25 17:51 ` [PATCH 7/7] ark3116: (3rd try) Cleanup of now unneeded functions bart.hartgers
2009-10-25 17:53 ` [PATCH 0/7] ark3116: (3rd try) driver rework Greg KH
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