From: Keith Packard <keithp@keithp.com>
To: Jean Delvare <jdelvare@suse.de>, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH 2/2] drm/kms: Use the standard VESA timeout for DDC channels
Date: Wed, 23 Nov 2011 13:24:33 -0800 [thread overview]
Message-ID: <867h2qedm6.fsf@sumi.keithp.com> (raw)
In-Reply-To: <201110210910.12848.jdelvare@suse.de>
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On Fri, 21 Oct 2011 09:10:12 +0200, Jean Delvare <jdelvare@suse.de> wrote:
> - /* vesa says 2.2 ms is enough, 1 jiffy doesn't seem to always
> - * make this, 2 jiffies is a lot more reliable */
> - i2c->algo.bit.timeout = 2;
> + i2c->algo.bit.timeout = usecs_to_jiffies(2200); /* from VESA */
From my reading of the usecs_to_jiffies code, it always returns a time
at least as long as requested, so this will ensure that you're waiting
at least 2.2ms, unlike 2 jiffies which is some random amount of time
depending on the HZ setting in the kernel.
Reviewed-by: Keith Packard <keithp@keithp.com>
--
keith.packard@intel.com
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prev parent reply other threads:[~2011-11-23 21:24 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-21 7:10 [PATCH 2/2] drm/kms: Use the standard VESA timeout for DDC channels Jean Delvare
2011-11-23 21:24 ` Keith Packard [this message]
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