From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CCE19C433E1 for ; Wed, 26 Aug 2020 07:05:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A16122067C for ; Wed, 26 Aug 2020 07:05:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726831AbgHZHFO (ORCPT ); Wed, 26 Aug 2020 03:05:14 -0400 Received: from mga01.intel.com ([192.55.52.88]:24662 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726719AbgHZHFM (ORCPT ); Wed, 26 Aug 2020 03:05:12 -0400 IronPort-SDR: 8A/AJ86Qc2Da2ndvc/Zax5Jdfe6nI0ETIIOd7XZZGvcbG0v+rdxitl1g6+ItbqkK481LYjU27m LrgqdP2muogQ== X-IronPort-AV: E=McAfee;i="6000,8403,9724"; a="174294095" X-IronPort-AV: E=Sophos;i="5.76,354,1592895600"; d="scan'208";a="174294095" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Aug 2020 00:05:11 -0700 IronPort-SDR: t9zAxUm+0FHTf119H7H8PV8/d7t15hFwVjWcUpPmVuSJw246+3dLtlSGJIJdZMZ+UVL+wne0mJ l9sOlDzxYKFg== X-IronPort-AV: E=Sophos;i="5.76,354,1592895600"; d="scan'208";a="474661934" Received: from jguenthe-mobl.ger.corp.intel.com (HELO localhost) ([10.252.32.223]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Aug 2020 00:05:04 -0700 From: Jani Nikula To: Lyude Paul , dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, nouveau@lists.freedesktop.org Cc: Sean Paul , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Joonas Lahtinen , Rodrigo Vivi , Ville =?utf-8?B?U3lyasOkbMOk?= , =?utf-8?Q?Jos=C3=A9?= Roberto de Souza , Manasi Navare , Uma Shankar , Gwan-gyeong Mun , Imre Deak , Wambui Karuga , Lucas De Marchi , open list Subject: Re: [RFC v4 16/20] drm/i915/dp: Extract drm_dp_get_sink_count() In-Reply-To: <20200825195027.74681-17-lyude@redhat.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20200825195027.74681-1-lyude@redhat.com> <20200825195027.74681-17-lyude@redhat.com> Date: Wed, 26 Aug 2020 10:05:01 +0300 Message-ID: <87o8mx6g6a.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 25 Aug 2020, Lyude Paul wrote: > And of course, we'll also need to read the sink count from other drivers > as well if we're checking whether or not it's supported. So, let's > extract the code for this into another helper. > > v2: > * Fix drm_dp_dpcd_readb() ret check > * Add back comment and move back sink_count assignment in intel_dp_get_dpcd() > > Signed-off-by: Lyude Paul > Reviewed-by: Sean Paul > --- > drivers/gpu/drm/drm_dp_helper.c | 22 ++++++++++++++++++++++ > drivers/gpu/drm/i915/display/intel_dp.c | 11 +++++------ > include/drm/drm_dp_helper.h | 1 + > 3 files changed, 28 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c > index 863e0babc1903..67ad05eb05b7e 100644 > --- a/drivers/gpu/drm/drm_dp_helper.c > +++ b/drivers/gpu/drm/drm_dp_helper.c > @@ -736,6 +736,28 @@ bool drm_dp_has_sink_count(struct drm_connector *connector, > } > EXPORT_SYMBOL(drm_dp_has_sink_count); > > +/** > + * drm_dp_get_sink_count() - Retrieve the sink count for a given sink >From the department of bikeshedding... Should we have a naming scheme where it's obvious whether a function will do DPCD access, or just shuffle existing data? For example, drm_dp_read_foo() for anything with DPCD access vs. drm_dp_get_foo() or even simpler for anything that only processes pre-read data? > + * @aux: The DP AUX channel to use > + * > + * Returns: The current sink count reported by @aux, or a negative error code > + * otherwise. > + */ > +int drm_dp_get_sink_count(struct drm_dp_aux *aux) > +{ > + u8 count; > + int ret; > + > + ret = drm_dp_dpcd_readb(aux, DP_SINK_COUNT, &count); > + if (ret < 0) > + return ret; > + if (ret != 1) > + return -EIO; Makes me wonder if that shouldn't be at drm_dp_dpcd_read() level, for reads returning 0..len-1 bytes. Not necessarily part of this series, but seems silly to set a precedent to start handling that return value all over the place. BR, Jani. > + > + return DP_GET_SINK_COUNT(count); > +} > +EXPORT_SYMBOL(drm_dp_get_sink_count); > + > /* > * I2C-over-AUX implementation > */ > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c > index 35a4779a442e2..4337321a3be4f 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp.c > +++ b/drivers/gpu/drm/i915/display/intel_dp.c > @@ -4648,6 +4648,8 @@ intel_dp_has_sink_count(struct intel_dp *intel_dp) > static bool > intel_dp_get_dpcd(struct intel_dp *intel_dp) > { > + int ret; > + > if (!intel_dp_read_dpcd(intel_dp)) > return false; > > @@ -4664,11 +4666,8 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp) > } > > if (intel_dp_has_sink_count(intel_dp)) { > - u8 count; > - ssize_t r; > - > - r = drm_dp_dpcd_readb(&intel_dp->aux, DP_SINK_COUNT, &count); > - if (r < 1) > + ret = drm_dp_get_sink_count(&intel_dp->aux); > + if (ret < 0) > return false; > > /* > @@ -4676,7 +4675,7 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp) > * a member variable in intel_dp will track any changes > * between short pulse interrupts. > */ > - intel_dp->sink_count = DP_GET_SINK_COUNT(count); > + intel_dp->sink_count = ret; > > /* > * SINK_COUNT == 0 and DOWNSTREAM_PORT_PRESENT == 1 implies that > diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h > index a1413a531eaf4..0c141fc81aaa8 100644 > --- a/include/drm/drm_dp_helper.h > +++ b/include/drm/drm_dp_helper.h > @@ -1635,6 +1635,7 @@ struct drm_dp_desc; > bool drm_dp_has_sink_count(struct drm_connector *connector, > const u8 dpcd[DP_RECEIVER_CAP_SIZE], > const struct drm_dp_desc *desc); > +int drm_dp_get_sink_count(struct drm_dp_aux *aux); > > void drm_dp_remote_aux_init(struct drm_dp_aux *aux); > void drm_dp_aux_init(struct drm_dp_aux *aux); -- Jani Nikula, Intel Open Source Graphics Center