Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755048AbbBQLCV (ORCPT ); Tue, 17 Feb 2015 06:02:21 -0500 Received: from mail-la0-f52.google.com ([209.85.215.52]:42770 "EHLO mail-la0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752089AbbBQLCT (ORCPT ); Tue, 17 Feb 2015 06:02:19 -0500 From: Ricardo Ribalda Delgado To: Hans Verkuil , Mauro Carvalho Chehab , Sylwester Nawrocki , Antti Palosaari , Sakari Ailus , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Ricardo Ribalda Delgado Subject: [PATCH] media/v4l2-ctrls: Always run s_ctrl on volatile ctrls Date: Tue, 17 Feb 2015 12:02:14 +0100 Message-Id: <1424170934-18619-1-git-send-email-ricardo.ribalda@gmail.com> X-Mailer: git-send-email 2.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1670 Lines: 47 Volatile controls can change their value outside the v4l-ctrl framework. We should ignore the cached written value of the ctrl when evaluating if we should run s_ctrl. Signed-off-by: Ricardo Ribalda Delgado --- I have a control that tells the user when there has been a external trigger overrun. (Trigger while processing old image). This is a volatile control. The user writes 0 to the control, to ack the error condition, and clear the hardware flag. Unfortunately, it only works one time, because the next time the user writes a zero to the control cluster_changed returns false. I think on volatile controls it is safer to run s_ctrl twice than missing a valid s_ctrl. I know I am abusing a bit the API for this :P, but I also believe that the semantic here is a bit confusing. drivers/media/v4l2-core/v4l2-ctrls.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c index 45c5b47..3d0c7f4 100644 --- a/drivers/media/v4l2-core/v4l2-ctrls.c +++ b/drivers/media/v4l2-core/v4l2-ctrls.c @@ -1605,7 +1605,7 @@ static int cluster_changed(struct v4l2_ctrl *master) for (i = 0; i < master->ncontrols; i++) { struct v4l2_ctrl *ctrl = master->cluster[i]; - bool ctrl_changed = false; + bool ctrl_changed = ctrl->flags & V4L2_CTRL_FLAG_VOLATILE; if (ctrl == NULL) continue; -- 2.1.4 -- 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/