From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from tim.rpsys.net (93-97-173-237.zone5.bethere.co.uk [93.97.173.237]) by yocto-www.yoctoproject.org (Postfix) with ESMTP id 86908E011B6 for ; Fri, 12 Aug 2011 06:08:34 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by tim.rpsys.net (8.13.6/8.13.8) with ESMTP id p7CD8aL0012039; Fri, 12 Aug 2011 14:08:36 +0100 Received: from tim.rpsys.net ([127.0.0.1]) by localhost (tim.rpsys.net [127.0.0.1]) (amavisd-new, port 10024) with LMTP id 11961-01; Fri, 12 Aug 2011 14:08:32 +0100 (BST) Received: from [192.168.3.10] ([192.168.3.10]) (authenticated bits=0) by tim.rpsys.net (8.13.6/8.13.8) with ESMTP id p7CD8SjH012033 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 12 Aug 2011 14:08:29 +0100 From: Richard Purdie To: Bruce Ashfield In-Reply-To: <4E44792F.5000402@windriver.com> References: <606861a92864cb728203fdf5db286d684d2537eb.1313090099.git.bruce.ashfield@windriver.com> <1313106445.14274.478.camel@rex> <4E44792F.5000402@windriver.com> Date: Fri, 12 Aug 2011 14:07:49 +0100 Message-ID: <1313154469.14274.489.camel@rex> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 X-Virus-Scanned: amavisd-new at rpsys.net Cc: poky@yoctoproject.org, Liming Wang , saul.wold@intel.com Subject: Re: [PATCH 1/1] meta-yocto: remove apm from beagleboard MACHINE_FEATURES X-BeenThere: poky@yoctoproject.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Poky build system developer discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 12 Aug 2011 13:08:35 -0000 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit On Thu, 2011-08-11 at 20:51 -0400, Bruce Ashfield wrote: > On 11-08-11 7:47 PM, Richard Purdie wrote: > > On Thu, 2011-08-11 at 15:16 -0400, Bruce Ashfield wrote: > >> Fixes [YOCTO: #916] > >> > >> apm is not something that we require in our yocto reference beagleboard > >> BSP. It currently is listed in the MACHINE_FEATURES for the board, which > >> leads to the runtime message: > >> > >> Starting advanced power management daemon: No APM support in kernel > >> > >> Since "/proc/apm" is not present. The board config we are targeting does > >> not have the hardware to back this, so adding the emulation support > >> wouldn't yield useful data. We'll leave this extended functionality for > >> other more appropriate beagleboard configs. > > > > On arm it used to be the case that this was the only way to expose user > > interface to suspend/resume the machine. Its not so much about their > > being hardware present for it as the whole kernel side was emulation of > > the user space notification part. > > > > Has something changed in recent kernels in this area? > > I won't claim to be an expert here .. but I haven't used apmd > on many machines in quite a while. Assuming suspend_ops is > implemented, it is typically just something ike this: > > echo mem > /sys/power/state > > or > > echo standby > /sys/power/state > > With a wakeup via the rtc, or whatever the board offers. I'm > cc'ing Liming on this, since he's been poking at the board recently > and may have more hands on information to share. > > If we ARE removing this capability, then we'll take the other option > that we had for this case and enable the emulation. I have a suspicion that certain parts of the sato code do assume /dev/apm_bios device emulation is present to get userspace notification of suspend/resume events which the above doesn't provide last I checked. Likely this isn't an issue and I think that code in sato (matchbox panel app iirc) is toggled by the MACHINE_FEATURES but its certainly worth keeping in mind... Cheers, Richard