Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935489Ab0BZHux (ORCPT ); Fri, 26 Feb 2010 02:50:53 -0500 Received: from out1.smtp.messagingengine.com ([66.111.4.25]:32832 "EHLO out1.smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935446Ab0BZHuw (ORCPT ); Fri, 26 Feb 2010 02:50:52 -0500 X-Greylist: delayed 727 seconds by postgrey-1.27 at vger.kernel.org; Fri, 26 Feb 2010 02:50:52 EST X-Sasl-enc: /mBT3yfGzT0WgdJ6UyBq6C9bPr/hoe3bgm91lUqiftSx 1267169925 Message-ID: <4B877A81.4030300@ladisch.de> Date: Fri, 26 Feb 2010 08:38:41 +0100 From: Clemens Ladisch User-Agent: Thunderbird 2.0.0.23 (Windows/20090812) MIME-Version: 1.0 To: Henrique de Moraes Holschuh CC: ibm-acpi-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: [PATCH] thinkpad-acpi: fix return value of volume callbacks References: <4B825228.8050405@ladisch.de> <20100223031220.GI30470@khazad-dum.debian.net> <4B83858C.8010305@ladisch.de> <20100226003056.GF5218@khazad-dum.debian.net> In-Reply-To: <20100226003056.GF5218@khazad-dum.debian.net> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1559 Lines: 33 Henrique de Moraes Holschuh wrote: > On Tue, 23 Feb 2010, Clemens Ladisch wrote: > > Henrique de Moraes Holschuh wrote: > > > On Mon, 22 Feb 2010, Clemens Ladisch wrote: > > > > Fix up the volume status setting functions to return a non-zero value if > > > > the control value has changed, so that the ALSA framework can correctly > > > > generate control change notifications. > > > > > > Please explain... > > > > ALSA sends notifications to all mixer application when the value of > > any mixer control has changed. To be able to avoid sending them for > > controls that did not actually change, it uses the return value of the > > .put callback: 0 means the control value did not change; 1 means it has > > changed (or might have changed), and a notification is to be sent. > > > > I am looking at it. I think I had it like that on purpose, to trigger an > OSD when a volume-related hotkey is pressed even if it doesn't change the > state (mute when already mute, vol down when already at minimum, etc). This is not about changes initiated by key presses but changes made through the ALSA mixer API. Or does the hardware generate a hotkey event when software changes the volume? Regards, Clemens -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/