From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757709AbdAIJES (ORCPT ); Mon, 9 Jan 2017 04:04:18 -0500 Received: from mail-wm0-f65.google.com ([74.125.82.65]:34251 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757575AbdAIJEI (ORCPT ); Mon, 9 Jan 2017 04:04:08 -0500 MIME-Version: 1.0 In-Reply-To: References: <20170106143029.11553-1-tomeu.vizoso@collabora.com> <20170106143029.11553-2-tomeu.vizoso@collabora.com> From: Tomeu Vizoso Date: Mon, 9 Jan 2017 10:03:46 +0100 X-Google-Sender-Auth: KS9zAvmae37RHo15KOqHI26RYYk Message-ID: Subject: Re: [PATCH v3 1/5] drm/dp: add connector backpointer to drm_dp_aux To: Sean Paul Cc: Linux Kernel Mailing List , =?UTF-8?B?VmlsbGUgU3lyasOkbMOk?= , Thierry Reding , intel-gfx-trybot@lists.freedesktop.org, Emil Velikov , Daniel Vetter , Benjamin Gaignard , Jani Nikula , dri-devel , David Airlie Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6 January 2017 at 16:56, Sean Paul wrote: > On Fri, Jan 6, 2017 at 9:30 AM, Tomeu Vizoso wrote: >> This backpointer allows DP helpers to access the connector it's being >> used for. >> >> Signed-off-by: Tomeu Vizoso >> --- >> >> include/drm/drm_dp_helper.h | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h >> index 55bbeb0ff594..4fa77b434594 100644 >> --- a/include/drm/drm_dp_helper.h >> +++ b/include/drm/drm_dp_helper.h >> @@ -721,6 +721,7 @@ struct drm_dp_aux_msg { >> * @name: user-visible name of this AUX channel and the I2C-over-AUX adapter >> * @ddc: I2C adapter that can be used for I2C-over-AUX communication >> * @dev: pointer to struct device that is the parent for this AUX channel >> + * @connector: backpointer to connector that uses this AUX channel >> * @hw_mutex: internal mutex used for locking transfers >> * @transfer: transfers a message representing a single AUX transaction >> * >> @@ -757,6 +758,7 @@ struct drm_dp_aux { >> const char *name; >> struct i2c_adapter ddc; >> struct device *dev; >> + struct drm_connector *connector; > > Perhaps I'm misreading the series, but it seems like you could instead > add int crc_pipe along with the other crc fields. Then when you start > the crc, set the pipe number. If you have the pipe in the crc worker, > you can wait vblank on that pipe (no pointers needed). > > Reasonable? I think that would work fine, but is it any better? I like that the connector isn't going to change during the lifetime of the drm_dp_aux, but crc_pipe could be changing between sampling sessions and any bugs in keeping that field updated would be quite disconcerting and cumbersome to debug. crc_pipe's advantage is that we wouldn't need to update all callers of drm_dp_aux_register, but I think it's better to have a connector field that is mistakenly NULL, than a crc_pipe field with the wrong value. Regards, Tomeu > Sean > >> struct mutex hw_mutex; >> ssize_t (*transfer)(struct drm_dp_aux *aux, >> struct drm_dp_aux_msg *msg); >> -- >> 2.9.3 >> > > > > -- > Sean Paul, Software Engineer, Google / Chromium OS