From mboxrd@z Thu Jan 1 00:00:00 1970 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= Subject: Re: [PATCH 1/1] Remove suspend/resume functionality, add dynamic clocking Date: Sun, 6 Dec 2009 22:02:25 +0100 Message-ID: <20091206210225.GA20887@pengutronix.de> References: <083DF309106F364B939360100EC290F804F55C9225@eu1rdcrdc1wx030.exi.nxp.com> <20091126090252.GB12179@pengutronix.de> <083DF309106F364B939360100EC290F804F5659CFF@eu1rdcrdc1wx030.exi.nxp.com> <20091206084731.GE2766@ucw.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <20091206084731.GE2766-+ZI9xUNit7I@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Pavel Machek Cc: Kevin Wells , Russell King - ARM Linux , "linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , Vitaly Wool List-Id: linux-i2c@vger.kernel.org Hi, On Sun, Dec 06, 2009 at 09:47:31AM +0100, Pavel Machek wrote: > Hi! >=20 > > > Subject: Re: [PATCH 1/1] Remove suspend/resume functionality, add= dynamic > > > clocking > > >=20 > > > Hello, > > >=20 > > > can you please add something like "i2c-pnx: " to the subject? > > > (Actually it's a great strategy *not* to put it into the Subject.= This > > > way it attracts far more attention :-) > > >=20 > >=20 > > Good point! > >=20 > > > > Remove suspend/resume functionality, I2C driver gates clock on > > > > only when an I2C transaction is in progress > > > What happens when the machine suspends while a transfer is in pro= gress? > > > (This might be a problem that already existed before.) If this i= s > > > really a problem the easiest "fix" is to let the suspend callback= return > > > -EBUSY in this case. > >=20 > > The suspend callback is now removed. It's actually not needed with = this > > change. The I2C clocks will turn on prior to a transaction and then= turn > > off at the completion. >=20 > Are you sure its unneeded? What if someone attempts to suspend the > system when a transaction is running? That's exactly my question. I think the machine will suspend and the transaction fail. So no suspend callback isn't optimal, but maybe OK?! Best regards Uwe --=20 Pengutronix e.K. | Uwe Kleine-K=F6nig = | Industrial Linux Solutions | http://www.pengutronix.= de/ |