From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753178AbeDIP1V (ORCPT ); Mon, 9 Apr 2018 11:27:21 -0400 Received: from mx08-00178001.pphosted.com ([91.207.212.93]:62267 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751662AbeDIP1T (ORCPT ); Mon, 9 Apr 2018 11:27:19 -0400 From: Philippe Cornu To: Laurent Pinchart , Daniel Vetter , Gustavo Padovan , "Maarten Lankhorst" , Sean Paul , David Airlie , , CC: Benjamin Gaignard , Yannick Fertre , Philippe Cornu , "Vincent Abriou" Subject: [PATCH] drm: clarify adjusted_mode documentation for bridges Date: Mon, 9 Apr 2018 17:24:27 +0200 Message-ID: <20180409152427.12449-1-philippe.cornu@st.com> X-Mailer: git-send-email 2.15.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.201.23.32] X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-04-09_07:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch clarifies the adjusted_mode documentation for bridges. Signed-off-by: Philippe Cornu Signed-off-by: Laurent Pinchart --- This patch follows discussions in: - "drm: clarify adjusted_mode for a bridge connected to a crtc" https://patchwork.freedesktop.org/patch/206801/ - "drm: bridge: Constify mode arguments to bridge .mode_set() operation" https://patchwork.freedesktop.org/patch/215449/ include/drm/drm_bridge.h | 16 ++++++++++++++++ include/drm/drm_crtc.h | 11 +++++++---- 2 files changed, 23 insertions(+), 4 deletions(-) diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h index 3270fec46979..7d632c6a9214 100644 --- a/include/drm/drm_bridge.h +++ b/include/drm/drm_bridge.h @@ -178,6 +178,22 @@ struct drm_bridge_funcs { * then this would be &drm_encoder_helper_funcs.mode_set. The display * pipe (i.e. clocks and timing signals) is off when this function is * called. + * + * The adjusted_mode parameter corresponds to the mode output by the CRTC + * for the first bridge in the chain. It can be different from the mode + * parameter that contains the desired mode for the connector at the end + * of the bridges chain, for instance when the first bridge in the chain + * performs scaling. The adjusted mode is mostly useful for the first + * bridge in the chain and is likely irrelevant for the other bridges. + * + * For atomic drivers the adjusted_mode is the mode stored in + * &drm_crtc_state.adjusted_mode. + * + * NOTE: + * + * If a need arises to store and access modes adjusted for other locations + * than the connection between the CRTC and the first bridge, the DRM + * framework will have to be extended with DRM bridge states. */ void (*mode_set)(struct drm_bridge *bridge, struct drm_display_mode *mode, diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h index a2d81d2907a9..65f749a9e9d3 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -134,10 +134,13 @@ struct drm_crtc_state { * * Internal display timings which can be used by the driver to handle * differences between the mode requested by userspace in @mode and what - * is actually programmed into the hardware. It is purely driver - * implementation defined what exactly this adjusted mode means. Usually - * it is used to store the hardware display timings used between the - * CRTC and encoder blocks. + * is actually programmed into the hardware. + * + * For drivers using drm_bridge, this stores the hardware display timings + * used between the CRTC and the first bridge. For other drivers, the + * meaning of the adjusted_mode field is purely driver implementation + * defined information, and will usually be used to store the hardware + * display timings used between the CRTC and encoder blocks. */ struct drm_display_mode adjusted_mode; -- 2.15.1