Re: V4L2 drivers: potentially dangerous and inefficient msecs_to_jiffies()calculation

From: Jiri Slaby
Date: Mon Sep 14 2009 - 17:35:00 EST


On 09/14/2009 11:07 PM, Andreas Mohr wrote:
> ./drivers/media/video/zc0301/zc0301_core.c
> do
> cam->module_param.frame_timeout *
> 1000 * msecs_to_jiffies(1) );
> multiple times each.
> What they should do instead is
> frame_timeout * msecs_to_jiffies(1000), I'd think.

In fact, msecs_to_jiffies(frame_timeout * 1000) makes much more sense.

> msecs_to_jiffies(1) is quite a bit too boldly assuming
> that all of the msecs_to_jiffies(x) implementation branches
> always round up.

They do, don't they?
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