From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f54.google.com (mail-wm1-f54.google.com [209.85.128.54]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DA4B1274670 for ; Mon, 27 Oct 2025 15:17:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.54 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761578277; cv=none; b=KI6v3jBmcEFlfAdtEYeliyAWHi/2YnKO/hR8Dd0UMaU6PU74lqch0MKq+UzQjr+pJWLWpw5vlqQWvlayo2+U7qcQCtrN5oEm5nVhs26t550HBCDffjLaCYzXU4k8Ss8pBamiXleq5AE4FhVXgXttG2cbRrFjdUfjXFRVV168qWw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761578277; c=relaxed/simple; bh=P031A4jtDENcUkWeKqo5uRLBpCPRmLPmmsdDBCRIa1s=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=AkLlheiuwE2c5ZvY/YBB+cce+9+d6Vc9z6cl9D2NJMViG5f8DpohDzQz2Slp3NdxN6exsM/CqHjHH4KKoAscSXDQ37iECPbCCvZCzpiNyBLrDyhuNsrcM42eeEJOODiEaWqpN02CNs63jh0XfFlawr9d9+rBq9qHqUBPGwX0hfY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=mUDyvvn0; arc=none smtp.client-ip=209.85.128.54 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="mUDyvvn0" Received: by mail-wm1-f54.google.com with SMTP id 5b1f17b1804b1-4770c34ca8eso13942225e9.0 for ; Mon, 27 Oct 2025 08:17:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1761578274; x=1762183074; darn=vger.kernel.org; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=EHnoeFxjinik7hVKNnr5X5XP1SZWgPi7b+K7uMiOxyo=; b=mUDyvvn08C2ZDSlGE8BACQOi+Wh8HJU9+PYacpn9GTcqiGnYe3LBg/Ok842taSyWYJ 7+aTTRGcG9HL33jLAfR5eucQNm+jFhdOMQ19lpbkvGe8jUBI85twLb+Ord+56wX9VqS9 i0FC5TKlXsdYRZ1Mc+pG6DS/D0fojMXMqd5mmXi3auey2bBAvrHGIGEeuAgZJ2zCTh8H fxh/SMt9X8ftjfSPZmJSUkt0538QCJz5CX5Rt9YnWgEA8pEtIn3l+UWabGrnx1aYvUKQ SPFbjLRxSESSBXNLQ7Avn7Q+qdMBdzOk5tgevO1891vHkH3kUqrFf72k9Ae0cnXLnlLD 5Xfg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1761578274; x=1762183074; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=EHnoeFxjinik7hVKNnr5X5XP1SZWgPi7b+K7uMiOxyo=; b=PhzzO053AMY7kA8JRObZ2Ln6e21ftw8Hz6HQJi5vMzWppcMte8BENAjAaACw9oNJ0D /SfKzgHkOs4phwHBjEPT7/Ch+euqx4WuT9jVGViCb2rh9q/JrFkEedS6DpLrxE7I2paq E9WnAUEFJTNebkSPNhDT67M38Y/UQpNfHndkr2A+15ZZDN3XUAQKwQa4CUHyLj35DDQl dvJBAGeTrIIk3nMdSN/K9fcv+h6u1HOxHSKbyIUb3R0hPVPa9oWXhUHjfu/+yhsb9bo4 iBiEyw5qFCgBS5kuOYUZNi1qO+h1aYR+c08pHnQJVJ9mrEwhRhYjb70GpW7qo/WozYVR 7sMA== X-Forwarded-Encrypted: i=1; AJvYcCV1QXAFkN59uPLRFk8KXR+8FLHLYUIi2W3lQEfTZd3aniDLa//8UNPQ7YPPEy4J0eLnVa7eZGRjac4=@vger.kernel.org X-Gm-Message-State: AOJu0YyRYAQ+rTwIRr3B3QTfLWB/mhHLP83XJUxsyDeMkgH08GOVjMua YrYDHq8QfA6mL/aipPm0E3PNtxkGinL7Bhl5oGGBdXRJFz60cihq/Yxj X-Gm-Gg: ASbGncvFHEprKCIeMQ3ldLd6oVODmmAhTd5MBhV3Shd27MByMg4HDobPNFQhGdaKB89 OOSRSDqTEEvdWPacaZB9m0ACXnfG3VtQMWvAIDxNxknk9I1UFk/JOR6xCxgC2r4F8sLuf3f5o/5 pV23Y026VB5WqrFBPLur+SMjfLM8gQr56RPt5PBnyu7fMToW9BWugYrDvuPlqHyDNUm0sHQoLFc Opazsst+aG2uK4BcSWv3gnZ4XXrSWxvB7wxsoPzOGid17MdQrhVvFVI8hN8RNvn12cKO7/Eoa8F Bcn+kEDlm8d0ASfrMqYPhylM9vu0oKHU7KUGskOdzN/pq7ewI7srrMl53Qx9zpor/D7mBXCpD/7 mfrIS875/hoe8QFqqeif0jx0LwWOtfgrhnd1ngG48Xwy2iMEys5s3Uf3qpD7NIczwGMnmXMB4eg == X-Google-Smtp-Source: AGHT+IFOtqqzmpz2GumwnMXeJudQB/bQ0NunpiqCBwdwJ3NphuydAK4zzTw+idu6gtpPu+OCGje9sA== X-Received: by 2002:a05:600c:4ed4:b0:45d:f83b:96aa with SMTP id 5b1f17b1804b1-47717df5505mr322525e9.7.1761578273978; Mon, 27 Oct 2025 08:17:53 -0700 (PDT) Received: from fedora ([94.73.38.14]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-475dcff9101sm72738225e9.1.2025.10.27.08.17.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Oct 2025 08:17:53 -0700 (PDT) Date: Mon, 27 Oct 2025 16:17:51 +0100 From: =?iso-8859-1?Q?Jos=E9_Exp=F3sito?= To: Louis Chauvet Cc: Haneen Mohammed , Simona Vetter , Melissa Wen , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Jonathan Corbet , victoria@system76.com, sebastian.wick@redhat.com, thomas.petazzoni@bootlin.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: [PATCH 22/22] drm/vkms: Allows the creation of connector at runtime Message-ID: References: <20251018-vkms-all-config-v1-0-a7760755d92d@bootlin.com> <20251018-vkms-all-config-v1-22-a7760755d92d@bootlin.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20251018-vkms-all-config-v1-22-a7760755d92d@bootlin.com> On Sat, Oct 18, 2025 at 04:01:22AM +0200, Louis Chauvet wrote: > DRM allows the connector to be created after the device. To allows > emulating this, add two configfs attributes to connector to allows this. > > Using the dynamic attribute you can set if a connector will be dynamic or > not. > Using the enabled attribute, you can set at runtime if a dynamic connector > is present or not. > > Co-developed-by: José Expósito > Signed-off-by: José Expósito > Signed-off-by: Louis Chauvet > --- > Documentation/gpu/vkms.rst | 6 +- > drivers/gpu/drm/vkms/vkms_configfs.c | 146 ++++++++++++++++++++++++++++++++--- > 2 files changed, 139 insertions(+), 13 deletions(-) > > diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst > index bbd03f61e61c..8b17aaa28eeb 100644 > --- a/Documentation/gpu/vkms.rst > +++ b/Documentation/gpu/vkms.rst > @@ -135,7 +135,7 @@ Last but not least, create one or more connectors:: > > sudo mkdir /config/vkms/my-vkms/connectors/connector0 > > -Connectors have 5 configurable attribute: > +Connectors have 7 configurable attribute: > > - status: Connection status: 1 connected, 2 disconnected, 3 unknown (same values > as those exposed by the "status" property of a connector) > @@ -147,7 +147,9 @@ Connectors have 5 configurable attribute: > - edid_enabled: Enable or not EDID for this connector. Some connectors may not have an > EDID but just a list of modes, this attribute allows to disable EDID property. > - edid: Content of the EDID. Ignored if edid_enabled is not set > - > +- dynamic: Set to 1 while configuring the device to create a dynamic connector. A dynamic > + connector can be used to emulate DP MST connectors. > +- enabled: For dynamic connector, set it to 1 to create the connector, 0 to remove it. > > To finish the configuration, link the different pipeline items:: > > diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c > index a977c0842cd6..937b749142ad 100644 > --- a/drivers/gpu/drm/vkms/vkms_configfs.c > +++ b/drivers/gpu/drm/vkms/vkms_configfs.c > @@ -1115,8 +1115,12 @@ static ssize_t connector_status_store(struct config_item *item, > scoped_guard(mutex, &connector->dev->lock) { > vkms_config_connector_set_status(connector->config, status); > > - if (connector->dev->enabled) > - vkms_trigger_connector_hotplug(connector->dev->config->dev); > + if (connector->dev->enabled) { > + if (connector->config->dynamic && connector->config->enabled) > + vkms_trigger_connector_hotplug(connector->dev->config->dev); > + if (!connector->config->dynamic) > + vkms_trigger_connector_hotplug(connector->dev->config->dev); To avoid duplicating code, we could do something like: bool hotplug = !connector->config->dynamic || (connector->config->dynamic && connector->config->enabled); if (hotplug) vkms_trigger_connector_hotplug(connector->dev->config->dev); > + } > } > > return (ssize_t)count; > @@ -1176,8 +1180,12 @@ static ssize_t connector_type_store(struct config_item *item, > } > > scoped_guard(mutex, &connector->dev->lock) { > - if (connector->dev->enabled) > - return -EINVAL; > + if (connector->dev->enabled) { > + if (connector->config->dynamic && connector->config->enabled) > + return -EBUSY; > + if (!connector->config->dynamic) > + return -EBUSY; > + } And something similar here. Also, instead of returning -EINVAL in "drm/vkms: Introduce configfs for connector type", you could return -EBUSY and avoid changing the return type here. > vkms_config_connector_set_type(connector->config, val); > } > > @@ -1293,6 +1301,102 @@ static ssize_t connector_edid_store(struct config_item *item, > connector_status_disconnected) > vkms_trigger_connector_hotplug(connector->dev->config->dev); > } > + return count; > +} > + > +static ssize_t connector_enabled_show(struct config_item *item, char *page) > +{ > + struct vkms_configfs_connector *connector; > + bool enabled; > + > + connector = connector_item_to_vkms_configfs_connector(item); > + > + scoped_guard(mutex, &connector->dev->lock) > + enabled = vkms_config_connector_is_enabled(connector->config); > + > + return sprintf(page, "%d\n", enabled); > +} > + > +static ssize_t connector_enabled_store(struct config_item *item, > + const char *page, size_t count) > +{ > + struct vkms_configfs_connector *connector; > + struct vkms_config_connector *connector_cfg; > + bool enabled, was_enabled; > + > + connector = connector_item_to_vkms_configfs_connector(item); > + connector_cfg = connector->config; > + > + if (kstrtobool(page, &enabled)) > + return -EINVAL; > + > + if (!connector->dev->enabled) { > + vkms_config_connector_set_enabled(connector_cfg, enabled); > + } else { > + // Only dynamic connector can be enabled/disabled at runtime > + if (!connector_cfg->dynamic) > + return -EBUSY; > + > + was_enabled = vkms_config_connector_is_enabled(connector_cfg); > + vkms_config_connector_set_enabled(connector_cfg, enabled); > + > + // Resulting configuration is invalid (missing encoder for example) > + // Early return to avoid drm core issue > + if (!vkms_config_is_valid(connector->dev->config)) { > + vkms_config_connector_set_enabled(connector_cfg, was_enabled); > + return -EINVAL; > + } > + > + if (!was_enabled && enabled) { > + // Adding the connector > + connector_cfg->connector = vkms_connector_hot_add(connector->dev->config->dev, > + connector_cfg); > + if (IS_ERR(connector_cfg->connector)) { > + vkms_config_connector_set_enabled(connector_cfg, was_enabled); > + return PTR_ERR(connector_cfg->connector); > + } > + } else if (was_enabled && !enabled) { > + vkms_connector_hot_remove(connector->dev->config->dev, > + connector_cfg->connector); > + } > + } > + return count; As a suggestion, we could add a "goto rollback;" and avoid duplicating error handling: rollback: vkms_config_connector_set_enabled(connector_cfg, was_enabled); return ret; > +} > + > +static ssize_t connector_dynamic_show(struct config_item *item, char *page) > +{ > + struct vkms_configfs_connector *connector; > + bool enabled; > + > + connector = connector_item_to_vkms_configfs_connector(item); > + > + scoped_guard(mutex, &connector->dev->lock) { > + enabled = vkms_config_connector_is_dynamic(connector->config); > + } > + > + return sprintf(page, "%d\n", enabled); > +} > + > +static ssize_t connector_dynamic_store(struct config_item *item, > + const char *page, size_t count) > +{ > + struct vkms_configfs_connector *connector; > + struct vkms_config_connector *connector_cfg; > + bool dynamic; > + > + connector = connector_item_to_vkms_configfs_connector(item); > + connector_cfg = connector->config; > + > + if (kstrtobool(page, &dynamic)) > + return -EINVAL; > + > + scoped_guard(mutex, &connector->dev->lock) { > + // Can't change the dynamic status when the device is activated > + if (connector->dev->enabled) > + return -EBUSY; > + > + vkms_config_connector_set_dynamic(connector_cfg, dynamic); > + } > > return count; > } > @@ -1302,6 +1406,8 @@ CONFIGFS_ATTR(connector_, type); > CONFIGFS_ATTR(connector_, supported_colorspaces); > CONFIGFS_ATTR(connector_, edid_enabled); > CONFIGFS_ATTR(connector_, edid); > +CONFIGFS_ATTR(connector_, dynamic); > +CONFIGFS_ATTR(connector_, enabled); > > static struct configfs_attribute *connector_item_attrs[] = { > &connector_attr_status, > @@ -1309,19 +1415,28 @@ static struct configfs_attribute *connector_item_attrs[] = { > &connector_attr_supported_colorspaces, > &connector_attr_edid_enabled, > &connector_attr_edid, > + &connector_attr_dynamic, > + &connector_attr_enabled, > NULL, > }; > > static void connector_release(struct config_item *item) > { > struct vkms_configfs_connector *connector; > + struct vkms_config_connector *connector_cfg; > struct mutex *lock; > > connector = connector_item_to_vkms_configfs_connector(item); > + connector_cfg = connector->config; > lock = &connector->dev->lock; > > scoped_guard(mutex, lock) { > + if (connector->dev->enabled && connector_cfg->dynamic && connector_cfg->enabled) > + vkms_connector_hot_remove(connector->dev->config->dev, > + connector_cfg->connector); > + > vkms_config_destroy_connector(connector->config); > + > kfree(connector); > } > } > @@ -1340,6 +1455,7 @@ static int connector_possible_encoders_allow_link(struct config_item *src, > struct config_item *target) > { > struct vkms_configfs_connector *connector; > + struct vkms_config_connector *connector_cfg; > struct vkms_configfs_encoder *encoder; > int ret; > > @@ -1347,16 +1463,25 @@ static int connector_possible_encoders_allow_link(struct config_item *src, > return -EINVAL; > > connector = connector_possible_encoders_item_to_vkms_configfs_connector(src); > + connector_cfg = connector->config; > encoder = encoder_item_to_vkms_configfs_encoder(target); > > scoped_guard(mutex, &connector->dev->lock) { > - if (connector->dev->enabled) > - return -EBUSY; > + if (connector->dev->enabled && connector_cfg->enabled) { > + if (!connector_cfg->dynamic) > + return -EBUSY; > + ret = vkms_connector_hot_attach_encoder(connector->dev->config->dev, > + connector->config->connector, > + encoder->config->encoder); > + if (ret) > + return ret; > + } > > ret = vkms_config_connector_attach_encoder(connector->config, > encoder->config); > + if (ret) > + return ret; > } > - > return ret; > } > > @@ -1394,9 +1519,6 @@ static struct config_group *make_connector_group(struct config_group *group, > dev = child_group_to_vkms_configfs_device(group); > > scoped_guard(mutex, &dev->lock) { > - if (dev->enabled) > - return ERR_PTR(-EBUSY); > - > connector = kzalloc(sizeof(*connector), GFP_KERNEL); > if (!connector) > return ERR_PTR(-ENOMEM); > @@ -1409,9 +1531,11 @@ static struct config_group *make_connector_group(struct config_group *group, > return ERR_CAST(connector->config); > } > > + vkms_config_connector_set_dynamic(connector->config, connector->dev->enabled); > + vkms_config_connector_set_enabled(connector->config, !connector->dev->enabled); > + > config_group_init_type_name(&connector->group, name, > &connector_item_type); > - > config_group_init_type_name(&connector->possible_encoders_group, > "possible_encoders", > &connector_possible_encoders_group_type); > > -- > 2.51.0 >