From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753266AbdEHS2X (ORCPT ); Mon, 8 May 2017 14:28:23 -0400 Received: from mail-qk0-f196.google.com ([209.85.220.196]:36714 "EHLO mail-qk0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751191AbdEHS2V (ORCPT ); Mon, 8 May 2017 14:28:21 -0400 Date: Mon, 8 May 2017 20:28:14 +0200 From: Daniel Vetter To: Jose Abreu Cc: Daniel Vetter , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Carlos Palminha , Alexey Brodkin , Ville =?iso-8859-1?Q?Syrj=E4l=E4?= , Dave Airlie , Andrzej Hajda , Archit Taneja Subject: Re: [PATCH 2/5] drm: Use new mode_valid() helpers in connector probe helper Message-ID: <20170508182814.5hnduzkkvuphygkh@phenom.ffwll.local> Mail-Followup-To: Jose Abreu , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Carlos Palminha , Alexey Brodkin , Ville =?iso-8859-1?Q?Syrj=E4l=E4?= , Dave Airlie , Andrzej Hajda , Archit Taneja References: <20170508075041.mj3z6572k67iv7nx@phenom.ffwll.local> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: 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 Mon, May 08, 2017 at 11:13:37AM +0100, Jose Abreu wrote: > Hi Daniel, > > > On 08-05-2017 08:50, Daniel Vetter wrote: > > On Thu, May 04, 2017 at 03:11:39PM +0100, Jose Abreu wrote: > >> This changes the connector probe helper function to use the new > >> encoder->mode_valid() and crtc->mode_valid() helper callbacks to > >> validate the modes. > >> > >> The new callbacks are optional so the behaviour remains the same > >> if they are not implemented. If they are, then the code loops > >> through all the connector's encodersXcrtcs and calls the > >> callback. > >> > >> If at least a valid encoderXcrtc combination is found which > >> accepts the mode then the function returns MODE_OK. > >> > >> 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 > > A few comments below. > > -Daniel > > Thanks for the review! > > > > >> --- > >> drivers/gpu/drm/drm_probe_helper.c | 71 +++++++++++++++++++++++++++++++++++--- > >> 1 file changed, 67 insertions(+), 4 deletions(-) > >> > >> diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c > >> index 1b0c14a..bf19f82 100644 > >> --- a/drivers/gpu/drm/drm_probe_helper.c > >> +++ b/drivers/gpu/drm/drm_probe_helper.c > >> @@ -80,6 +80,67 @@ > >> return MODE_OK; > >> } > >> > >> +static enum drm_mode_status > >> +drm_mode_validate_connector(struct drm_connector *connector, > >> + struct drm_display_mode *mode) > >> +{ > >> + const struct drm_connector_helper_funcs *connector_funcs = > >> + connector->helper_private; > >> + struct drm_device *dev = connector->dev; > >> + uint32_t *ids = connector->encoder_ids; > >> + enum drm_mode_status ret = MODE_OK; > >> + unsigned int i; > >> + > >> + /* Step 1: Validate against connector */ > >> + if (connector_funcs && connector_funcs->mode_valid) > >> + ret = connector_funcs->mode_valid(connector, mode); > >> + > >> + if (ret != MODE_OK) > >> + return ret; > >> + > >> + /* Step 2: Validate against encoders and crtcs */ > >> + for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) { > >> + struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]); > >> + const struct drm_encoder_helper_funcs *encoder_funcs; > >> + struct drm_crtc *crtc; > >> + > >> + if (!encoder) > >> + continue; > >> + > >> + encoder_funcs = encoder->helper_private; > >> + if (encoder_funcs && encoder_funcs->mode_valid) > >> + ret = encoder_funcs->mode_valid(encoder, mode); > >> + else > >> + ret = MODE_OK; /* encoder accepts everything */ > >> + > >> + /* No point in continuing for crtc check as this encoder will > >> + * not accept the mode anyway. If all encoders reject the mode > >> + * then, at exit, ret will not be MODE_OK. */ > >> + if (ret != MODE_OK) > >> + continue; > > I think we should validate encoders against connector->possible_ids here. > > Might be that not many drivers fill this out correctly, and in case fixing > > that is much work, perhaps as a follow-up. But would be good to at least > > help look down that part of uapi a bit more. > > I'm sorry but I'm not following you here (I think I need more > coffee :)). > > What do you mean by connector->possible_ids ? Is this something > new ? Because I didn't find anything in my tree and I'm based on > today's drm-next from Dave. Oops, I guess I was on an old tree or whatever by accident. I meant drm_connector->encoder_ids, that limits the encoders you can use on a crtc. For many drivers there's only one. > > This isn't checked within atomic and legacy helpers since we assume that > > ->best_encoder respectively ->atomic_best_encoder gives us a valid encoder > > ... > > > >> + > >> + drm_for_each_crtc(crtc, dev) { > >> + const struct drm_crtc_helper_funcs *crtc_funcs; > >> + > >> + if (!drm_encoder_crtc_ok(encoder, crtc)) > >> + continue; > > We check this one here already in both atomic and legacy helpers, so all > > drivers should get this right. > > But drm_for_each_crtc() iterates over all crtc from a device and > some crtcs may only be used by specific encoders (by setting > encoder->possible_crtcs), right ? We need to iterate only over > the encoder's crtc we want to validate. This was a comment about ->encoder_ids, since we don't validate that in the atomic helpers (but instead rely on ->(atomic_)best_encoder to give us the right encoder) validating here in this function might be a problem and uncover driver bugs. But for drm_encoder_crtc_ok there's no such risk, so this is safe. I was simply dumping my thoughts while reviewing, the code is all good :-) Cheers, Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch