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=-8.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 E2F17C432C0 for ; Mon, 2 Dec 2019 17:03:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ABF7820848 for ; Mon, 2 Dec 2019 17:03:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="apOvdzYF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727655AbfLBRDr (ORCPT ); Mon, 2 Dec 2019 12:03:47 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:37456 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727601AbfLBRDr (ORCPT ); Mon, 2 Dec 2019 12:03:47 -0500 Received: from pendragon.ideasonboard.com (81-175-216-236.bb.dnainternet.fi [81.175.216.236]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 4AE5E309; Mon, 2 Dec 2019 18:03:43 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1575306223; bh=8B+MR8jgFupVuPJxryWnFCiBjXyLZ/cVdPkv8Ba1+qM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=apOvdzYFSdlagm+i+zqVCUMIKhvVQTzAhyK/NVntLaQyfQAfj1cUTyY85wattpfR5 bWJfCxdHdbYmaV86h4Bv1eHLjqak2qi1PzM4/ssWApc9ZUEGkDsHBr5oh0D/Ktxbzv fPQdZ28aHvO/LUaJ4HHXfD6RrwN3+4qNCW21rS4k= Date: Mon, 2 Dec 2019 19:03:36 +0200 From: Laurent Pinchart To: Boris Brezillon Cc: dri-devel@lists.freedesktop.org, Lucas Stach , Chris Healy , Andrey Smirnov , Nikita Yushchenko , kernel@collabora.com, Daniel Vetter , Inki Dae , Joonyoung Shim , Seung-Woo Kim , Kyungmin Park , Thierry Reding , Sam Ravnborg , Philipp Zabel , Rob Clark , Andrzej Hajda , Neil Armstrong , Jonas Karlman , Jernej Skrabec , Rob Herring , Mark Rutland , devicetree@vger.kernel.org Subject: Re: [PATCH v3 12/21] drm/bridge: Add an ->atomic_check() hook Message-ID: <20191202170336.GP4929@pendragon.ideasonboard.com> References: <20191023154512.9762-1-boris.brezillon@collabora.com> <20191023154512.9762-13-boris.brezillon@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20191023154512.9762-13-boris.brezillon@collabora.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi Boris, Thank you for the patch. On Wed, Oct 23, 2019 at 05:45:03PM +0200, Boris Brezillon wrote: > So that bridge drivers have a way to check/reject an atomic operation. > The drm_atomic_bridge_chain_check() (which is just a wrapper around > the ->atomic_check() hook) is called in place of > drm_bridge_chain_mode_fixup() (when ->atomic_check() is not implemented, > the core falls back on ->mode_fixup(), so the behavior should stay > the same for existing bridge drivers). > > Signed-off-by: Boris Brezillon > --- > Changes in v3: > * None > > Changes in v2: > * Clarify the fact that ->atomic_check() is replacing ->mode_fixup() > --- > drivers/gpu/drm/drm_atomic_helper.c | 12 +++--- > drivers/gpu/drm/drm_bridge.c | 62 +++++++++++++++++++++++++++++ > include/drm/drm_bridge.h | 29 +++++++++++++- > 3 files changed, 96 insertions(+), 7 deletions(-) > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c > index de985ba7ce2d..1d0a19511a0d 100644 > --- a/drivers/gpu/drm/drm_atomic_helper.c > +++ b/drivers/gpu/drm/drm_atomic_helper.c > @@ -437,12 +437,12 @@ mode_fixup(struct drm_atomic_state *state) > funcs = encoder->helper_private; > > bridge = drm_bridge_chain_get_first_bridge(encoder); > - ret = drm_bridge_chain_mode_fixup(bridge, > - &new_crtc_state->mode, > - &new_crtc_state->adjusted_mode); > - if (!ret) { > - DRM_DEBUG_ATOMIC("Bridge fixup failed\n"); > - return -EINVAL; > + ret = drm_atomic_bridge_chain_check(bridge, > + new_crtc_state, > + new_conn_state); > + if (ret) { > + DRM_DEBUG_ATOMIC("Bridge atomic check failed\n"); > + return ret; > } > > if (funcs && funcs->atomic_check) { > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c > index 377866e3214f..990e056296bd 100644 > --- a/drivers/gpu/drm/drm_bridge.c > +++ b/drivers/gpu/drm/drm_bridge.c > @@ -615,6 +615,68 @@ void drm_atomic_bridge_chain_enable(struct drm_bridge *bridge, > } > EXPORT_SYMBOL(drm_atomic_bridge_chain_enable); > > +static int drm_atomic_bridge_check(struct drm_bridge *bridge, > + struct drm_crtc_state *crtc_state, > + struct drm_connector_state *conn_state) > +{ > + if (bridge->funcs->atomic_check) { > + struct drm_bridge_state *bridge_state; > + int ret; > + > + bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state, > + bridge); > + if (WARN_ON(!bridge_state)) > + return -EINVAL; > + > + ret = bridge->funcs->atomic_check(bridge, bridge_state, > + crtc_state, conn_state); > + if (ret) > + return ret; > + } else if (bridge->funcs->mode_fixup) { > + if (!bridge->funcs->mode_fixup(bridge, &crtc_state->mode, > + &crtc_state->adjusted_mode)) > + return -EINVAL; > + } > + > + return 0; > +} > + > +/** > + * drm_atomic_bridge_chain_check() - Do an atomic check on the bridge chain > + * @bridge: bridge control structure > + * @crtc_state: new CRTC state > + * @conn_state: new connector state > + * > + * Calls &drm_bridge_funcs.atomic_check() (falls back on > + * &drm_bridge_funcs.mode_fixup()) op for all the bridges in the encoder chain, > + * starting from the last bridge to the first. These are called before calling > + * &drm_encoder_helper_funcs.atomic_check() > + * > + * RETURNS: > + * 0 on success, a negative error code on failure > + */ > +int drm_atomic_bridge_chain_check(struct drm_bridge *bridge, > + struct drm_crtc_state *crtc_state, > + struct drm_connector_state *conn_state) > +{ > + struct drm_encoder *encoder = bridge->encoder; > + struct drm_bridge *iter; > + > + list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) { > + int ret; > + > + ret = drm_atomic_bridge_check(iter, crtc_state, conn_state); > + if (ret) > + return ret; > + > + if (iter == bridge) > + break; > + } > + > + return 0; > +} > +EXPORT_SYMBOL(drm_atomic_bridge_chain_check); > + > /** > * drm_atomic_helper_bridge_destroy_state() - Default destroy state helper > * @bridge: the bridge this state refers to > diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h > index b1f557d8dba9..2beb1ef9a733 100644 > --- a/include/drm/drm_bridge.h > +++ b/include/drm/drm_bridge.h > @@ -127,7 +127,9 @@ struct drm_bridge_funcs { > * this function passes all other callbacks must succeed for this > * configuration. > * > - * The @mode_fixup callback is optional. > + * The mode_fixup callback is optional. &drm_bridge_funcs.mode_fixup() > + * is not called when &drm_bridge_funcs.atomic_check() is implemented, > + * so only one of them should be provided. > * > * NOTE: > * > @@ -391,6 +393,28 @@ struct drm_bridge_funcs { > void (*atomic_destroy_state)(struct drm_bridge *bridge, > struct drm_bridge_state *state); > > + /** > + * @atomic_check: > + * > + * This method is responsible for checking bridge state correctness. > + * It can also check the state of the surrounding components in chain > + * to make sure the whole pipeline can work properly. As explained in the review of the RFC, I think it's a mistake not to define the semantics of this operation precisely, and in particular not to define explictly what parameters bridge drivers are allowed to modify here. I however don't want to make this a prerequisite for your series, so Reviewed-by: Laurent Pinchart but I'm sure we'll regret this later when different bridges will have slightly incompatible implementations. > + * > + * &drm_bridge_funcs.atomic_check() hooks are called in reverse > + * order (from the last to the first bridge). > + * > + * This method is optional. &drm_bridge_funcs.mode_fixup() is not > + * called when &drm_bridge_funcs.atomic_check() is implemented, so only > + * one of them should be provided. > + * > + * RETURNS: > + * zero if the check passed, a negative error code otherwise. > + */ > + int (*atomic_check)(struct drm_bridge *bridge, > + struct drm_bridge_state *bridge_state, > + struct drm_crtc_state *crtc_state, > + struct drm_connector_state *conn_state); > + > /** > * @atomic_reset: > * > @@ -542,6 +566,9 @@ void drm_bridge_chain_mode_set(struct drm_bridge *bridge, > void drm_bridge_chain_pre_enable(struct drm_bridge *bridge); > void drm_bridge_chain_enable(struct drm_bridge *bridge); > > +int drm_atomic_bridge_chain_check(struct drm_bridge *bridge, > + struct drm_crtc_state *crtc_state, > + struct drm_connector_state *conn_state); > void drm_atomic_bridge_chain_disable(struct drm_bridge *bridge, > struct drm_atomic_state *state); > void drm_atomic_bridge_chain_post_disable(struct drm_bridge *bridge, -- Regards, Laurent Pinchart