2007-11-15 22:50:50

by Andrew Morton

[permalink] [raw]
Subject: Re: [PATCH 3/4] bas_gigaset: suspend support (v2)

On Tue, 13 Nov 2007 18:30:30 +0100 (CET)
Tilman Schmidt <[email protected]> wrote:

> From: Tilman Schmidt <[email protected]>
>
> This patch adds basic suspend/resume support to the bas_gigaset ISDN
> driver for the Siemens Gigaset SX255 series of ISDN DECT bases.
>
> Only the USB aspects are handled so far; the ISDN subsystem is not
> notified in any way, for lack of information about how to do that.
> The driver will refuse to suspend if a connection is active.
>
> ...
>
> + if (atomic_read(&cs->hw.bas->basstate) & BS_SUSPEND) {

that's pretty peculiar. We'd only expect to see atomics being used in
conjunction with atomic_add/sub/inc/etc. Here the driver is using an
atomic_t as a state variable. And here's the magic bit:

spin_lock_irqsave(&ucs->lock, flags);
state = atomic_read(&ucs->basstate);
atomic_set(&ucs->basstate, (state & ~clear) | set);
spin_unlock_irqrestore(&ucs->lock, flags);

I'm suspecting that a plain old `int' would be more appropriate here.


2007-11-15 23:51:19

by Tilman Schmidt

[permalink] [raw]
Subject: Re: [PATCH 3/4] bas_gigaset: suspend support (v2)

Am 15.11.2007 23:50 schrieb Andrew Morton:
>> ...
>>
>> + if (atomic_read(&cs->hw.bas->basstate) & BS_SUSPEND) {
>
> that's pretty peculiar. We'd only expect to see atomics being used in
> conjunction with atomic_add/sub/inc/etc. Here the driver is using an
> atomic_t as a state variable. And here's the magic bit:
>
> spin_lock_irqsave(&ucs->lock, flags);
> state = atomic_read(&ucs->basstate);
> atomic_set(&ucs->basstate, (state & ~clear) | set);
> spin_unlock_irqrestore(&ucs->lock, flags);
>
> I'm suspecting that a plain old `int' would be more appropriate here.

You're right. That's a prehistoric leftover. That variable was
originally accessed using atomic_set_mask() and atomic_clear_mask()
which are unfortunately x86 platform specific.

I'll prepare a cleanup patch.

Thanks,
Tilman

--
Tilman Schmidt E-Mail: [email protected]
Bonn, Germany
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