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=-8.2 required=3.0 tests=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 DE5D8C433E0 for ; Wed, 8 Jul 2020 18:45:29 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C44D72065D for ; Wed, 8 Jul 2020 18:45:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C44D72065D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4D9256E911; Wed, 8 Jul 2020 18:45:29 +0000 (UTC) Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by gabe.freedesktop.org (Postfix) with ESMTPS id F3F176E911 for ; Wed, 8 Jul 2020 18:45:27 +0000 (UTC) IronPort-SDR: sGZG5sA0Z2ub12LtI9+HZBfqYfPeEJ4I/iPsnRVQR/eAi4TGrGU/KVSRPZgJI+plrS4XuJIg2U KpOutsmnHwHw== X-IronPort-AV: E=McAfee;i="6000,8403,9676"; a="136121182" X-IronPort-AV: E=Sophos;i="5.75,328,1589266800"; d="scan'208";a="136121182" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Jul 2020 11:45:26 -0700 IronPort-SDR: 6I9X6m+Z61OZ8Atkmrna7xxMRQP1yGd6+RImi/UozIiV1cdsHkepI0iXwZLJKTsebq1bn4HcWs kkG1UOH0M/fg== X-IronPort-AV: E=Sophos;i="5.75,328,1589266800"; d="scan'208";a="457610227" Received: from ideak-desk.fi.intel.com ([10.237.68.147]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Jul 2020 11:45:25 -0700 Date: Wed, 8 Jul 2020 21:45:21 +0300 From: Imre Deak To: Lyude Paul Subject: Re: [PATCH 1/2] drm/probe_helper: Add drm_connector_helper_funcs.mode_valid_ctx Message-ID: <20200708184521.GC21536@ideak-desk.fi.intel.com> References: <20200526182313.4005-1-lyude@redhat.com> <20200526182313.4005-2-lyude@redhat.com> <20200707224036.GA22747@ideak-desk.fi.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: imre.deak@intel.com Cc: David Airlie , Thomas Zimmermann , Lee Shawn C , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Wed, Jul 08, 2020 at 01:25:14PM -0400, Lyude Paul wrote: > > JFYI - found an issue with this patch that wouldn't have shown up on i915, info > down below: > > On Wed, 2020-07-08 at 01:40 +0300, Imre Deak wrote: > > Sorry for the delay, the review as I promised: > > > > On Tue, May 26, 2020 at 02:23:09PM -0400, Lyude Paul wrote: > > > This is just an atomic version of mode_valid, which is intended to be > > > used for situations where a driver might need to check the atomic state > > > of objects other than the connector itself. One such example is with > > > MST, where the maximum possible bandwidth on a connector can change > > > dynamically irregardless of the display configuration. > > > > > > Signed-off-by: Lyude Paul > > > Cc: Lee Shawn C > > > Tested-by: Lee Shawn C > > > --- > > > drivers/gpu/drm/drm_crtc_helper_internal.h | 6 +- > > > drivers/gpu/drm/drm_probe_helper.c | 65 ++++++++++++++-------- > > > include/drm/drm_modeset_helper_vtables.h | 41 ++++++++++++++ > > > 3 files changed, 88 insertions(+), 24 deletions(-) > > > > > > diff --git a/drivers/gpu/drm/drm_crtc_helper_internal.h > > > b/drivers/gpu/drm/drm_crtc_helper_internal.h > > > index f0a66ef47e5ad..ca767cba6094d 100644 > > > --- a/drivers/gpu/drm/drm_crtc_helper_internal.h > > > +++ b/drivers/gpu/drm/drm_crtc_helper_internal.h > > > @@ -73,8 +73,10 @@ enum drm_mode_status drm_crtc_mode_valid(struct drm_crtc > > > *crtc, > > > const struct drm_display_mode *mode); > > > enum drm_mode_status drm_encoder_mode_valid(struct drm_encoder *encoder, > > > const struct drm_display_mode > > > *mode); > > > -enum drm_mode_status drm_connector_mode_valid(struct drm_connector > > > *connector, > > > - struct drm_display_mode *mode); > > > +enum drm_mode_status > > > +drm_connector_mode_valid(struct drm_connector *connector, > > > + struct drm_display_mode *mode, > > > + struct drm_modeset_acquire_ctx *ctx); > > > > > > struct drm_encoder * > > > drm_connector_get_single_encoder(struct drm_connector *connector); > > > diff --git a/drivers/gpu/drm/drm_probe_helper.c > > > b/drivers/gpu/drm/drm_probe_helper.c > > > index 466dfbba82564..3132784736841 100644 > > > --- a/drivers/gpu/drm/drm_probe_helper.c > > > +++ b/drivers/gpu/drm/drm_probe_helper.c > > > @@ -86,16 +86,17 @@ drm_mode_validate_flag(const struct drm_display_mode > > > *mode, > > > return MODE_OK; > > > } > > > > > > -static enum drm_mode_status > > > +static int > > > drm_mode_validate_pipeline(struct drm_display_mode *mode, > > > - struct drm_connector *connector) > > > + struct drm_connector *connector, > > > + struct drm_modeset_acquire_ctx *ctx) > > > { > > > struct drm_device *dev = connector->dev; > > > - enum drm_mode_status ret = MODE_OK; > > > struct drm_encoder *encoder; > > > + int ret = MODE_OK; > > > > > > /* Step 1: Validate against connector */ > > > - ret = drm_connector_mode_valid(connector, mode); > > > + ret = drm_connector_mode_valid(connector, mode, ctx); > > > if (ret != MODE_OK) > > > return ret; > > > > > > @@ -196,16 +197,23 @@ enum drm_mode_status drm_encoder_mode_valid(struct > > > drm_encoder *encoder, > > > return encoder_funcs->mode_valid(encoder, mode); > > > } > > > > > > -enum drm_mode_status drm_connector_mode_valid(struct drm_connector > > > *connector, > > > - struct drm_display_mode *mode) > > > +int > > > +drm_connector_mode_valid(struct drm_connector *connector, > > > + struct drm_display_mode *mode, > > > + struct drm_modeset_acquire_ctx *ctx) > > > { > > > const struct drm_connector_helper_funcs *connector_funcs = > > > connector->helper_private; > > > > > > - if (!connector_funcs || !connector_funcs->mode_valid) > > > + if (!connector_funcs) > > > return MODE_OK; > > > > > > - return connector_funcs->mode_valid(connector, mode); > > > + if (connector_funcs->mode_valid_ctx) > > > + return connector_funcs->mode_valid_ctx(connector, mode, ctx); > > > + else if (connector_funcs->mode_valid) > > > + return connector_funcs->mode_valid(connector, mode); > > > + else > > > + return MODE_OK; > > > } > > > > > > #define DRM_OUTPUT_POLL_PERIOD (10*HZ) > > > @@ -375,8 +383,9 @@ EXPORT_SYMBOL(drm_helper_probe_detect); > > > * (if specified) > > > * - drm_mode_validate_flag() checks the modes against basic connector > > > * capabilities (interlace_allowed,doublescan_allowed,stereo_allowed) > > > - * - the optional &drm_connector_helper_funcs.mode_valid helper can > > > perform > > > - * driver and/or sink specific checks > > > + * - the optional &drm_connector_helper_funcs.mode_valid or > > > + * &drm_connector_helper_funcs.mode_valid_ctx helpers can perform > > > driver > > > + * and/or sink specific checks > > > * - the optional &drm_crtc_helper_funcs.mode_valid, > > > * &drm_bridge_funcs.mode_valid and > > > &drm_encoder_helper_funcs.mode_valid > > > * helpers can perform driver and/or source specific checks which are > > > also > > > @@ -507,22 +516,34 @@ int drm_helper_probe_single_connector_modes(struct > > > drm_connector *connector, > > > mode_flags |= DRM_MODE_FLAG_3D_MASK; > > > > > > list_for_each_entry(mode, &connector->modes, head) { > > > - if (mode->status == MODE_OK) > > > - mode->status = drm_mode_validate_driver(dev, mode); > > > + if (mode->status != MODE_OK) > > > + continue; > > > + > > > + mode->status = drm_mode_validate_driver(dev, mode); > > > + if (mode->status != MODE_OK) > > > + continue; > > > > > > - if (mode->status == MODE_OK) > > > - mode->status = drm_mode_validate_size(mode, maxX, maxY); > > > + mode->status = drm_mode_validate_size(mode, maxX, maxY); > > > + if (mode->status != MODE_OK) > > > + continue; > > > > > > - if (mode->status == MODE_OK) > > > - mode->status = drm_mode_validate_flag(mode, mode_flags); > > > + mode->status = drm_mode_validate_flag(mode, mode_flags); > > > + if (mode->status != MODE_OK) > > > + continue; > > > > > > - if (mode->status == MODE_OK) > > > - mode->status = drm_mode_validate_pipeline(mode, > > > - connector); > > > + ret = drm_mode_validate_pipeline(mode, connector, &ctx); > > > + if (ret == -EDEADLK) { > > > + drm_modeset_backoff(&ctx); > > > + goto retry; > > > + } else if (WARN_ON_ONCE(ret < 0)) { > > > + mode->status = MODE_BAD; > > This check is wrong actually. We define negative values for drm_mode_status > (MODE_BAD, MODE_ERROR, MODE_STALE) which, at least with how drivers currently > seem to use them, are something we want to treat as not-unexpected errors and > not WARN_ON. Ah, yes, missed that. > This is a bit annoying because it does mean there's some overlap between > drm_mode_status and some legitimate errno values (EPERM, ENOENT, ESRCH). Luckily > I can't see any reason why drivers would want to return those, but I think we > should probably print a debugging message when we get any errno values just so > developers don't get confused (also going to add a IS_ERR() equivalent for > drm_mode_status, but with a different name) Maybe I'm missing something, but having negative values in drm_mode_status doesn't make sense to me, as all the non-zero values there just mean the mode is incorrect for some reason and should be pruned. Would it make sense to better separate the mode-status value and any error return value from mode_valid_ctx(), by adding a drm_mode_status * parameter to the hook and drm_mode_validate_pipeline()? > > > > + } else { > > > + mode->status = ret; > > > + } > > > > > > - if (mode->status == MODE_OK) > > > - mode->status = drm_mode_validate_ycbcr420(mode, > > > - connector); > > > + if (mode->status != MODE_OK) > > > + continue; > > > + mode->status = drm_mode_validate_ycbcr420(mode, connector); > > > } > > > > > > prune: > > > diff --git a/include/drm/drm_modeset_helper_vtables.h > > > b/include/drm/drm_modeset_helper_vtables.h > > > index 421a30f084631..8f020c3424b2b 100644 > > > --- a/include/drm/drm_modeset_helper_vtables.h > > > +++ b/include/drm/drm_modeset_helper_vtables.h > > > @@ -968,6 +968,47 @@ struct drm_connector_helper_funcs { > > > */ > > > enum drm_mode_status (*mode_valid)(struct drm_connector *connector, > > > struct drm_display_mode *mode); > > > + > > > + /** > > > + * @mode_valid_ctx: > > > + * > > > + * Callback to validate a mode for a connector, irrespective of the > > > + * specific display configuration. > > > + * > > > + * This callback is used by the probe helpers to filter the mode list > > > + * (which is usually derived from the EDID data block from the sink). > > > + * See e.g. drm_helper_probe_single_connector_modes(). > > > + * > > > + * This function is optional, and is the atomic version of > > > + * &drm_connector_funcs.mode_valid. > > > + * > > > + * To allow for accessing the atomic state of modesetting objects, the > > > + * helper libraries always call this with ctx set to a valid context, > > > + * and &drm_mode_config.connection_mutex will always be locked with > > > + * the ctx parameter set to @ctx. This allows for taking additional > > > + * locks as required. > > > + * > > > + * Even though additional locks may be acquired, this callback is > > > + * still expected not to take any constraints into account which would > > > + * be influenced by the currently set display state - such constraints > > > + * should be handled in the driver's atomic check. For example, if a > > > + * connector shares display bandwidth with other connectors then it > > > + * would be ok to validate a mode uses against the maximum possible > > ^mode against? > > > > Reviewed-by: Imre Deak > > > > > + * bandwidth of the connector. But it wouldn't be ok to take the > > > + * current bandwidth usage of other connectors into account, as this > > > + * would change depending on the display state. > > > + * > > > + * Returns: > > > + * > > > + * Either &drm_mode_status.MODE_OK, one of the failure reasons in > > > + * &enum drm_mode_status, or -EDEADLK if a deadlock would have > > > + * occurred and we need to backoff. > > > + * > > > + */ > > > + int (*mode_valid_ctx)(struct drm_connector *connector, > > > + struct drm_display_mode *mode, > > > + struct drm_modeset_acquire_ctx *ctx); > > > + > > > /** > > > * @best_encoder: > > > * > > > -- > > > 2.26.2 > > > > > > _______________________________________________ > > > dri-devel mailing list > > > dri-devel@lists.freedesktop.org > > > https://lists.freedesktop.org/mailman/listinfo/dri-devel > _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel