From: Evgeniy Polyakov <zbr@ioremap.net>
To: Maciej Szmigiero <mhej@o2.pl>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Christian Glindkamp <christian.glindkamp@taskit.de>,
linux-kernel@vger.kernel.org, Greg KH <greg@kroah.com>
Subject: Re: [PATCH][W1]w1_therm: release the bus during conversion on externally powered devices
Date: Thu, 17 Nov 2011 16:32:20 +0300 [thread overview]
Message-ID: <20111117133220.GA28213@ioremap.net> (raw)
In-Reply-To: <4EC2F914.4010302@o2.pl>
+gregkh
On Wed, Nov 16, 2011 at 12:43:16AM +0100, Maciej Szmigiero (mhej@o2.pl) wrote:
> w1_therm devices can either be bus powered or externally powered.
>
> When device is bus powered during temperature conversion the bus
> have to be left high to provide necessary power. Some masters also allow
> strong power-up to be enabled in this case.
> Naturally, no communication over bus can occur during that time.
>
> However, if device has external power then there is no such restriction,
> and host can talk to other devices during temperature conversion.
>
> There is command which allows us to check how device is powered,
> this patch uses it to release the bus on externally w1_therm powered devices
> during temperature conversion.
>
> Also, this changes uninterruptible sleeps there into interruptible ones to
> avoid long uninterruptible sleep if w1 subsystem happens to grab bus for
> scan during w1_therm_read().
Patch looks good, but I do not have such hardware to test it.
So, if it doesn't break things I'm ok to push it upstream.
Greg, please pull it into your tree, thank you.
> Signed-off-by: Maciej Szmigiero <mhej@o2.pl>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
--
Evgeniy Polyakov
prev parent reply other threads:[~2011-11-17 13:41 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-15 23:43 Maciej Szmigiero
2011-11-17 13:32 ` Evgeniy Polyakov [this message]
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