From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753435AbdEJPOi (ORCPT ); Wed, 10 May 2017 11:14:38 -0400 Received: from mail-wr0-f195.google.com ([209.85.128.195]:36607 "EHLO mail-wr0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752837AbdEJPOh (ORCPT ); Wed, 10 May 2017 11:14:37 -0400 Date: Wed, 10 May 2017 17:14:33 +0200 From: Daniel Vetter To: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Cc: Jose Abreu , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Carlos Palminha , Alexey Brodkin , Daniel Vetter , Dave Airlie , Andrzej Hajda , Archit Taneja Subject: Re: [PATCH v2 6/8] drm: Introduce drm_bridge_mode_valid() Message-ID: <20170510151433.7ewizmeeidrqonan@phenom.ffwll.local> Mail-Followup-To: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= , Jose Abreu , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Carlos Palminha , Alexey Brodkin , Dave Airlie , Andrzej Hajda , Archit Taneja References: <20170510134109.GF12629@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20170510134109.GF12629@intel.com> X-Operating-System: Linux phenom 4.9.0-2-amd64 User-Agent: NeoMutt/20170306 (1.8.0) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 10, 2017 at 04:41:09PM +0300, Ville Syrjälä wrote: > On Tue, May 09, 2017 at 06:00:13PM +0100, Jose Abreu wrote: > > Introduce a new helper function which calls mode_valid() callback > > for all bridges in an encoder chain. > > > > Signed-off-by: Jose Abreu > > Cc: Carlos Palminha > > Cc: Alexey Brodkin > > Cc: Ville Syrjälä > > Cc: Daniel Vetter > > Cc: Dave Airlie > > Cc: Andrzej Hajda > > Cc: Archit Taneja > > --- > > drivers/gpu/drm/drm_bridge.c | 33 +++++++++++++++++++++++++++++++++ > > include/drm/drm_bridge.h | 2 ++ > > 2 files changed, 35 insertions(+) > > > > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c > > index 86a7637..dc8cdfe 100644 > > --- a/drivers/gpu/drm/drm_bridge.c > > +++ b/drivers/gpu/drm/drm_bridge.c > > @@ -206,6 +206,39 @@ bool drm_bridge_mode_fixup(struct drm_bridge *bridge, > > EXPORT_SYMBOL(drm_bridge_mode_fixup); > > > > /** > > + * drm_bridge_mode_valid - validate the mode against all bridges in the > > + * encoder chain. > > + * @bridge: bridge control structure > > + * @mode: desired mode to be validated > > + * > > + * Calls &drm_bridge_funcs.mode_valid for all the bridges in the encoder > > + * chain, starting from the first bridge to the last. If at least one bridge > > + * does not accept the mode the function returns the error code. > > + * > > + * Note: the bridge passed should be the one closest to the encoder. > > + * > > + * RETURNS: > > + * MODE_OK on success, drm_mode_status Enum error code on failure > > + */ > > +enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge, > > + const struct drm_display_mode *mode) > > +{ > > + enum drm_mode_status ret = MODE_OK; > > + > > + if (!bridge) > > + return ret; > > + > > + if (bridge->funcs->mode_valid) > > + ret = bridge->funcs->mode_valid(bridge, mode); > > + > > + if (ret != MODE_OK) > > + return ret; > > + > > + return drm_bridge_mode_valid(bridge->next, mode); > > Looks like it should be pretty trivial to avoid the recursion. > > Am I correct in interpreting this that bridges have some kind of > a hand rolled linked list implementation? Reusing the standard > linked lists would allow you to use list_for_each() etc. Yeah it's a hand-rolled list, but current hw also has a bridge nesting depth of 2, so it really doesn't matter. I guess once we have real long chains of bridges we can fix this (and just using list_head sounds like a great idea). -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch