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=-5.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 CFE36C433FF for ; Tue, 30 Jul 2019 07:04:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 85F0F20882 for ; Tue, 30 Jul 2019 07:04:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564470290; bh=FcM+uxIwrSFEfd5JbmB2ItmwtS88WV6LGASvj5Dcn/8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=bU584Jn4IuEe8GUv4L51QAGXuiZ5vxuMschX1p/MgpbQfeKST7UrUTRyvZOhuF7lz 8PUtZGEjfTe6Cxu1DUyRDidji0yia47Ovo7xEI28I9z+kU9+R4fnXAXLunphqmytjI Zi5Z/QisjhJ4/G0doeCXJOJcn2xNtCimIlYZZAlw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729495AbfG3HEt (ORCPT ); Tue, 30 Jul 2019 03:04:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:41212 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728663AbfG3HEt (ORCPT ); Tue, 30 Jul 2019 03:04:49 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 24B9820882; Tue, 30 Jul 2019 07:04:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564470285; bh=FcM+uxIwrSFEfd5JbmB2ItmwtS88WV6LGASvj5Dcn/8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QNSONUmgawJEZiQfmBh0WzeoscDh4mx9xhh9yPw+EKrviP1wwHXVPaz9+i45iYEhB InjOBD7oc2kA2tTInKagpDIcdt3V7q2KlWEw92sHTqZtoSG6DZfEJ1xm2X2PDxhn6B I/U6QJj3NJHao7zGnnaVajJwCDr1KIlXy0kiyVrA= Date: Tue, 30 Jul 2019 09:04:43 +0200 From: Greg Kroah-Hartman To: "Rafael J. Wysocki" Cc: Dmitry Osipenko , LKML , Linux PM , Saravana Kannan , Lukas Wunner , Jon Hunter , Ulf Hansson , Marek Szyprowski , "linux-tegra@vger.kernel.org" , Thierry Reding Subject: Re: [PATCH v2] driver core: Remove device link creation limitation Message-ID: <20190730070443.GB10125@kroah.com> References: <2305283.AStDPdUUnE@kreacher> <7944678.tFQQHhpDPp@kreacher> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <7944678.tFQQHhpDPp@kreacher> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Mon, Jul 29, 2019 at 11:50:05PM +0200, Rafael J. Wysocki wrote: > On Monday, July 29, 2019 5:48:57 PM CEST Dmitry Osipenko wrote: > > 16.07.2019 18:21, Rafael J. Wysocki пишет: > > > From: Rafael J. Wysocki > > > Subject: [PATCH] driver core: Remove device link creation limitation > > > > > > If device_link_add() is called for a consumer/supplier pair with an > > > existing device link between them and the existing link's type is > > > not in agreement with the flags passed to that function by its > > > caller, NULL will be returned. That is seriously inconvenient, > > > because it forces the callers of device_link_add() to worry about > > > what others may or may not do even if that is not relevant to them > > > for any other reasons. > > > > > > It turns out, however, that this limitation can be made go away > > > relatively easily. > > > > > > The underlying observation is that if DL_FLAG_STATELESS has been > > > passed to device_link_add() in flags for the given consumer/supplier > > > pair at least once, calling either device_link_del() or > > > device_link_remove() to release the link returned by it should work, > > > but there are no other requirements associated with that flag. In > > > turn, if at least one of the callers of device_link_add() for the > > > given consumer/supplier pair has not passed DL_FLAG_STATELESS to it > > > in flags, the driver core should track the status of the link and act > > > on it as appropriate (ie. the link should be treated as "managed"). > > > This means that DL_FLAG_STATELESS needs to be set for managed device > > > links and it should be valid to call device_link_del() or > > > device_link_remove() to drop references to them in certain > > > sutiations. > > > > > > To allow that to happen, introduce a new (internal) device link flag > > > called DL_FLAG_MANAGED and make device_link_add() set it automatically > > > whenever DL_FLAG_STATELESS is not passed to it. Also make it take > > > additional references to existing device links that were previously > > > stateless (that is, with DL_FLAG_STATELESS set and DL_FLAG_MANAGED > > > unset) and will need to be managed going forward and initialize > > > their status (which has been DL_STATE_NONE so far). > > > > > > Accordingly, when a managed device link is dropped automatically > > > by the driver core, make it clear DL_FLAG_MANAGED, reset the link's > > > status back to DL_STATE_NONE and drop the reference to it associated > > > with DL_FLAG_MANAGED instead of just deleting it right away (to > > > allow it to stay around in case it still needs to be released > > > explicitly by someone). > > > > > > With that, since setting DL_FLAG_STATELESS doesn't mean that the > > > device link in question is not managed any more, replace all of the > > > status-tracking checks against DL_FLAG_STATELESS with analogous > > > checks against DL_FLAG_MANAGED and update the documentation to > > > reflect these changes. > > > > > > While at it, make device_link_add() reject flags that it does not > > > recognize, including DL_FLAG_MANAGED. > > > > > > Signed-off-by: Rafael J. Wysocki > > > Reviewed-by: Saravana Kannan > > > Tested-by: Marek Szyprowski > > > --- > > > > > > -> v2: > > > * Add a check to device_link_add() to return NULL if unrecognized flags are > > > passed to it. > > > * Modify kerneldoc comments around DL_FLAG_MANAGED. > > > > > > I've tentatively added the Tested-by tag from Marek, because I don't expect > > > the changes made between the initial posting and the v2 to make any difference > > > for him. > > > > > > --- > > > Documentation/driver-api/device_link.rst | 4 > > > drivers/base/core.c | 176 +++++++++++++++++-------------- > > > drivers/base/power/runtime.c | 4 > > > include/linux/device.h | 4 > > > 4 files changed, 106 insertions(+), 82 deletions(-) > > > > > > Index: linux-pm/drivers/base/core.c > > > =================================================================== > > > --- linux-pm.orig/drivers/base/core.c > > > +++ linux-pm/drivers/base/core.c > > > @@ -124,6 +124,50 @@ static int device_is_dependent(struct de > > > return ret; > > > } > > > > > > +static void device_link_init_status(struct device_link *link, > > > + struct device *consumer, > > > + struct device *supplier) > > > +{ > > > + switch (supplier->links.status) { > > > + case DL_DEV_PROBING: > > > + switch (consumer->links.status) { > > > + case DL_DEV_PROBING: > > > + /* > > > + * A consumer driver can create a link to a supplier > > > + * that has not completed its probing yet as long as it > > > + * knows that the supplier is already functional (for > > > + * example, it has just acquired some resources from the > > > + * supplier). > > > + */ > > > + link->status = DL_STATE_CONSUMER_PROBE; > > > + break; > > > + default: > > > + link->status = DL_STATE_DORMANT; > > > + break; > > > + } > > > + break; > > > + case DL_DEV_DRIVER_BOUND: > > > + switch (consumer->links.status) { > > > + case DL_DEV_PROBING: > > > + link->status = DL_STATE_CONSUMER_PROBE; > > > + break; > > > + case DL_DEV_DRIVER_BOUND: > > > + link->status = DL_STATE_ACTIVE; > > > + break; > > > + default: > > > + link->status = DL_STATE_AVAILABLE; > > > + break; > > > + } > > > + break; > > > + case DL_DEV_UNBINDING: > > > + link->status = DL_STATE_SUPPLIER_UNBIND; > > > + break; > > > + default: > > > + link->status = DL_STATE_DORMANT; > > > + break; > > > + } > > > +} > > > + > > > static int device_reorder_to_tail(struct device *dev, void *not_used) > > > { > > > struct device_link *link; > > > @@ -165,6 +209,10 @@ void device_pm_move_to_tail(struct devic > > > device_links_read_unlock(idx); > > > } > > > > > > +#define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \ > > > + DL_FLAG_AUTOREMOVE_SUPPLIER | \ > > > + DL_FLAG_AUTOPROBE_CONSUMER) > > > + > > > /** > > > * device_link_add - Create a link between two devices. > > > * @consumer: Consumer end of the link. > > > @@ -179,9 +227,9 @@ void device_pm_move_to_tail(struct devic > > > * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be > > > * ignored. > > > * > > > - * If DL_FLAG_STATELESS is set in @flags, the link is not going to be managed by > > > - * the driver core and, in particular, the caller of this function is expected > > > - * to drop the reference to the link acquired by it directly. > > > + * If DL_FLAG_STATELESS is set in @flags, the caller of this function is > > > + * expected to release the link returned by it directly with the help of either > > > + * device_link_del() or device_link_remove(). > > > * > > > * If that flag is not set, however, the caller of this function is handing the > > > * management of the link over to the driver core entirely and its return value > > > @@ -201,9 +249,16 @@ void device_pm_move_to_tail(struct devic > > > * be used to request the driver core to automaticall probe for a consmer > > > * driver after successfully binding a driver to the supplier device. > > > * > > > - * The combination of DL_FLAG_STATELESS and either DL_FLAG_AUTOREMOVE_CONSUMER > > > - * or DL_FLAG_AUTOREMOVE_SUPPLIER set in @flags at the same time is invalid and > > > - * will cause NULL to be returned upfront. > > > + * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER, > > > + * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at > > > + * the same time is invalid and will cause NULL to be returned upfront. > > > + * However, if a device link between the given @consumer and @supplier pair > > > + * exists already when this function is called for them, the existing link will > > > + * be returned regardless of its current type and status (the link's flags may > > > + * be modified then). The caller of this function is then expected to treat > > > + * the link as though it has just been created, so (in particular) if > > > + * DL_FLAG_STATELESS was passed in @flags, the link needs to be released > > > + * explicitly when not needed any more (as stated above). > > > * > > > * A side effect of the link creation is re-ordering of dpm_list and the > > > * devices_kset list by moving the consumer device and all devices depending > > > @@ -220,10 +275,8 @@ struct device_link *device_link_add(stru > > > struct device_link *link; > > > > > > if (!consumer || !supplier || > > > - (flags & DL_FLAG_STATELESS && > > > - flags & (DL_FLAG_AUTOREMOVE_CONSUMER | > > > - DL_FLAG_AUTOREMOVE_SUPPLIER | > > > - DL_FLAG_AUTOPROBE_CONSUMER)) || > > > + (flags & ~(DL_FLAG_STATELESS | DL_MANAGED_LINK_FLAGS)) || > > > + (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) || > > > (flags & DL_FLAG_AUTOPROBE_CONSUMER && > > > flags & (DL_FLAG_AUTOREMOVE_CONSUMER | > > > DL_FLAG_AUTOREMOVE_SUPPLIER))) > > > @@ -236,6 +289,9 @@ struct device_link *device_link_add(stru > > > } > > > } > > > > > > + if (!(flags & DL_FLAG_STATELESS)) > > > + flags |= DL_FLAG_MANAGED; > > > + > > > device_links_write_lock(); > > > device_pm_lock(); > > > > > > @@ -262,15 +318,6 @@ struct device_link *device_link_add(stru > > > if (link->consumer != consumer) > > > continue; > > > > > > - /* > > > - * Don't return a stateless link if the caller wants a stateful > > > - * one and vice versa. > > > - */ > > > - if (WARN_ON((flags & DL_FLAG_STATELESS) != (link->flags & DL_FLAG_STATELESS))) { > > > - link = NULL; > > > - goto out; > > > - } > > > - > > > if (flags & DL_FLAG_PM_RUNTIME) { > > > if (!(link->flags & DL_FLAG_PM_RUNTIME)) { > > > pm_runtime_new_link(consumer); > > > @@ -281,6 +328,7 @@ struct device_link *device_link_add(stru > > > } > > > > > > if (flags & DL_FLAG_STATELESS) { > > > + link->flags |= DL_FLAG_STATELESS; > > > kref_get(&link->kref); > > > goto out; > > > } > > > @@ -299,6 +347,11 @@ struct device_link *device_link_add(stru > > > link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER | > > > DL_FLAG_AUTOREMOVE_SUPPLIER); > > > } > > > + if (!(link->flags & DL_FLAG_MANAGED)) { > > > + kref_get(&link->kref); > > > + link->flags |= DL_FLAG_MANAGED; > > > + device_link_init_status(link, consumer, supplier); > > > + } > > > goto out; > > > } > > > > > > @@ -325,48 +378,10 @@ struct device_link *device_link_add(stru > > > kref_init(&link->kref); > > > > > > /* Determine the initial link state. */ > > > - if (flags & DL_FLAG_STATELESS) { > > > + if (flags & DL_FLAG_STATELESS) > > > link->status = DL_STATE_NONE; > > > - } else { > > > - switch (supplier->links.status) { > > > - case DL_DEV_PROBING: > > > - switch (consumer->links.status) { > > > - case DL_DEV_PROBING: > > > - /* > > > - * A consumer driver can create a link to a > > > - * supplier that has not completed its probing > > > - * yet as long as it knows that the supplier is > > > - * already functional (for example, it has just > > > - * acquired some resources from the supplier). > > > - */ > > > - link->status = DL_STATE_CONSUMER_PROBE; > > > - break; > > > - default: > > > - link->status = DL_STATE_DORMANT; > > > - break; > > > - } > > > - break; > > > - case DL_DEV_DRIVER_BOUND: > > > - switch (consumer->links.status) { > > > - case DL_DEV_PROBING: > > > - link->status = DL_STATE_CONSUMER_PROBE; > > > - break; > > > - case DL_DEV_DRIVER_BOUND: > > > - link->status = DL_STATE_ACTIVE; > > > - break; > > > - default: > > > - link->status = DL_STATE_AVAILABLE; > > > - break; > > > - } > > > - break; > > > - case DL_DEV_UNBINDING: > > > - link->status = DL_STATE_SUPPLIER_UNBIND; > > > - break; > > > - default: > > > - link->status = DL_STATE_DORMANT; > > > - break; > > > - } > > > - } > > > + else > > > + device_link_init_status(link, consumer, supplier); > > > > > > /* > > > * Some callers expect the link creation during consumer driver probe to > > > @@ -528,7 +543,7 @@ static void device_links_missing_supplie > > > * mark the link as "consumer probe in progress" to make the supplier removal > > > * wait for us to complete (or bad things may happen). > > > * > > > - * Links with the DL_FLAG_STATELESS flag set are ignored. > > > + * Links without the DL_FLAG_MANAGED flag set are ignored. > > > */ > > > int device_links_check_suppliers(struct device *dev) > > > { > > > @@ -538,7 +553,7 @@ int device_links_check_suppliers(struct > > > device_links_write_lock(); > > > > > > list_for_each_entry(link, &dev->links.suppliers, c_node) { > > > - if (link->flags & DL_FLAG_STATELESS) > > > + if (!(link->flags & DL_FLAG_MANAGED)) > > > continue; > > > > > > if (link->status != DL_STATE_AVAILABLE) { > > > @@ -563,7 +578,7 @@ int device_links_check_suppliers(struct > > > * > > > * Also change the status of @dev's links to suppliers to "active". > > > * > > > - * Links with the DL_FLAG_STATELESS flag set are ignored. > > > + * Links without the DL_FLAG_MANAGED flag set are ignored. > > > */ > > > void device_links_driver_bound(struct device *dev) > > > { > > > @@ -572,7 +587,7 @@ void device_links_driver_bound(struct de > > > device_links_write_lock(); > > > > > > list_for_each_entry(link, &dev->links.consumers, s_node) { > > > - if (link->flags & DL_FLAG_STATELESS) > > > + if (!(link->flags & DL_FLAG_MANAGED)) > > > continue; > > > > > > /* > > > @@ -593,7 +608,7 @@ void device_links_driver_bound(struct de > > > } > > > > > > list_for_each_entry(link, &dev->links.suppliers, c_node) { > > > - if (link->flags & DL_FLAG_STATELESS) > > > + if (!(link->flags & DL_FLAG_MANAGED)) > > > continue; > > > > > > WARN_ON(link->status != DL_STATE_CONSUMER_PROBE); > > > @@ -605,6 +620,13 @@ void device_links_driver_bound(struct de > > > device_links_write_unlock(); > > > } > > > > > > +static void device_link_drop_managed(struct device_link *link) > > > +{ > > > + link->flags &= ~DL_FLAG_MANAGED; > > > + WRITE_ONCE(link->status, DL_STATE_NONE); > > > + kref_put(&link->kref, __device_link_del); > > > +} > > > + > > > /** > > > * __device_links_no_driver - Update links of a device without a driver. > > > * @dev: Device without a drvier. > > > @@ -615,18 +637,18 @@ void device_links_driver_bound(struct de > > > * unless they already are in the "supplier unbind in progress" state in which > > > * case they need not be updated. > > > * > > > - * Links with the DL_FLAG_STATELESS flag set are ignored. > > > + * Links without the DL_FLAG_MANAGED flag set are ignored. > > > */ > > > static void __device_links_no_driver(struct device *dev) > > > { > > > struct device_link *link, *ln; > > > > > > list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) { > > > - if (link->flags & DL_FLAG_STATELESS) > > > + if (!(link->flags & DL_FLAG_MANAGED)) > > > continue; > > > > > > if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) > > > - __device_link_del(&link->kref); > > > + device_link_drop_managed(link); > > > else if (link->status == DL_STATE_CONSUMER_PROBE || > > > link->status == DL_STATE_ACTIVE) > > > WRITE_ONCE(link->status, DL_STATE_AVAILABLE); > > > @@ -643,7 +665,7 @@ static void __device_links_no_driver(str > > > * %__device_links_no_driver() to update links to suppliers for it as > > > * appropriate. > > > * > > > - * Links with the DL_FLAG_STATELESS flag set are ignored. > > > + * Links without the DL_FLAG_MANAGED flag set are ignored. > > > */ > > > void device_links_no_driver(struct device *dev) > > > { > > > @@ -652,7 +674,7 @@ void device_links_no_driver(struct devic > > > device_links_write_lock(); > > > > > > list_for_each_entry(link, &dev->links.consumers, s_node) { > > > - if (link->flags & DL_FLAG_STATELESS) > > > + if (!(link->flags & DL_FLAG_MANAGED)) > > > continue; > > > > > > /* > > > @@ -680,7 +702,7 @@ void device_links_no_driver(struct devic > > > * invoke %__device_links_no_driver() to update links to suppliers for it as > > > * appropriate. > > > * > > > - * Links with the DL_FLAG_STATELESS flag set are ignored. > > > + * Links without the DL_FLAG_MANAGED flag set are ignored. > > > */ > > > void device_links_driver_cleanup(struct device *dev) > > > { > > > @@ -689,7 +711,7 @@ void device_links_driver_cleanup(struct > > > device_links_write_lock(); > > > > > > list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) { > > > - if (link->flags & DL_FLAG_STATELESS) > > > + if (!(link->flags & DL_FLAG_MANAGED)) > > > continue; > > > > > > WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER); > > > @@ -702,7 +724,7 @@ void device_links_driver_cleanup(struct > > > */ > > > if (link->status == DL_STATE_SUPPLIER_UNBIND && > > > link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER) > > > - __device_link_del(&link->kref); > > > + device_link_drop_managed(link); > > > > > > WRITE_ONCE(link->status, DL_STATE_DORMANT); > > > } > > > @@ -724,7 +746,7 @@ void device_links_driver_cleanup(struct > > > * > > > * Return 'false' if there are no probing or active consumers. > > > * > > > - * Links with the DL_FLAG_STATELESS flag set are ignored. > > > + * Links without the DL_FLAG_MANAGED flag set are ignored. > > > */ > > > bool device_links_busy(struct device *dev) > > > { > > > @@ -734,7 +756,7 @@ bool device_links_busy(struct device *de > > > device_links_write_lock(); > > > > > > list_for_each_entry(link, &dev->links.consumers, s_node) { > > > - if (link->flags & DL_FLAG_STATELESS) > > > + if (!(link->flags & DL_FLAG_MANAGED)) > > > continue; > > > > > > if (link->status == DL_STATE_CONSUMER_PROBE > > > @@ -764,7 +786,7 @@ bool device_links_busy(struct device *de > > > * driver to unbind and start over (the consumer will not re-probe as we have > > > * changed the state of the link already). > > > * > > > - * Links with the DL_FLAG_STATELESS flag set are ignored. > > > + * Links without the DL_FLAG_MANAGED flag set are ignored. > > > */ > > > void device_links_unbind_consumers(struct device *dev) > > > { > > > @@ -776,7 +798,7 @@ void device_links_unbind_consumers(struc > > > list_for_each_entry(link, &dev->links.consumers, s_node) { > > > enum device_link_state status; > > > > > > - if (link->flags & DL_FLAG_STATELESS) > > > + if (!(link->flags & DL_FLAG_MANAGED)) > > > continue; > > > > > > status = link->status; > > > Index: linux-pm/drivers/base/power/runtime.c > > > =================================================================== > > > --- linux-pm.orig/drivers/base/power/runtime.c > > > +++ linux-pm/drivers/base/power/runtime.c > > > @@ -1624,7 +1624,7 @@ void pm_runtime_remove(struct device *de > > > * runtime PM references to the device, drop the usage counter of the device > > > * (as many times as needed). > > > * > > > - * Links with the DL_FLAG_STATELESS flag set are ignored. > > > + * Links with the DL_FLAG_MANAGED flag unset are ignored. > > > * > > > * Since the device is guaranteed to be runtime-active at the point this is > > > * called, nothing else needs to be done here. > > > @@ -1641,7 +1641,7 @@ void pm_runtime_clean_up_links(struct de > > > idx = device_links_read_lock(); > > > > > > list_for_each_entry_rcu(link, &dev->links.consumers, s_node) { > > > - if (link->flags & DL_FLAG_STATELESS) > > > + if (!(link->flags & DL_FLAG_MANAGED)) > > > continue; > > > > > > while (refcount_dec_not_one(&link->rpm_active)) > > > Index: linux-pm/include/linux/device.h > > > =================================================================== > > > --- linux-pm.orig/include/linux/device.h > > > +++ linux-pm/include/linux/device.h > > > @@ -829,12 +829,13 @@ enum device_link_state { > > > /* > > > * Device link flags. > > > * > > > - * STATELESS: The core won't track the presence of supplier/consumer drivers. > > > + * STATELESS: The core will not remove this link automatically. > > > * AUTOREMOVE_CONSUMER: Remove the link automatically on consumer driver unbind. > > > * PM_RUNTIME: If set, the runtime PM framework will use this link. > > > * RPM_ACTIVE: Run pm_runtime_get_sync() on the supplier during link creation. > > > * AUTOREMOVE_SUPPLIER: Remove the link automatically on supplier driver unbind. > > > * AUTOPROBE_CONSUMER: Probe consumer driver automatically after supplier binds. > > > + * MANAGED: The core tracks presence of supplier/consumer drivers (internal). > > > */ > > > #define DL_FLAG_STATELESS BIT(0) > > > #define DL_FLAG_AUTOREMOVE_CONSUMER BIT(1) > > > @@ -842,6 +843,7 @@ enum device_link_state { > > > #define DL_FLAG_RPM_ACTIVE BIT(3) > > > #define DL_FLAG_AUTOREMOVE_SUPPLIER BIT(4) > > > #define DL_FLAG_AUTOPROBE_CONSUMER BIT(5) > > > +#define DL_FLAG_MANAGED BIT(6) > > > > > > /** > > > * struct device_link - Device link representation. > > > Index: linux-pm/Documentation/driver-api/device_link.rst > > > =================================================================== > > > --- linux-pm.orig/Documentation/driver-api/device_link.rst > > > +++ linux-pm/Documentation/driver-api/device_link.rst > > > @@ -78,8 +78,8 @@ typically deleted in its ``->remove`` ca > > > driver is compiled as a module, the device link is added on module load and > > > orderly deleted on unload. The same restrictions that apply to device link > > > addition (e.g. exclusion of a parallel suspend/resume transition) apply equally > > > -to deletion. Device links with ``DL_FLAG_STATELESS`` unset (i.e. managed > > > -device links) are deleted automatically by the driver core. > > > +to deletion. Device links managed by the driver core are deleted automatically > > > +by it. > > > > > > Several flags may be specified on device link addition, two of which > > > have already been mentioned above: ``DL_FLAG_STATELESS`` to express that no > > > > > > > > > > > > > > > > Hello Rafael, > > > > This patch breaks NVIDIA Tegra DRM driver, which fails to probe now > > using the recent linux-next. > > > > tegra-dc 54240000.dc: failed to link controllers > > > > Thanks for the report and sorry for the breakage! > > My bad, obviously DL_FLAG_PM_RUNTIME must be accepted by device_link_add(), > as well as DL_FLAG_RPM_ACTIVE. > > Please test the appended patch and let me know if it helps. > > Greg, in case this is confirmed to fix the issue, do you want me to post it as a > separate patch, or would you prefer a v3 of the $subject one? Separate patch please, I can't rebase my tree. thanks, greg k-h