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Subject: Re: [PATCH] driver core: Fix creation of device links with
 PM-runtime flags
To:     "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Linux PM <linux-pm@vger.kernel.org>,
        Saravana Kannan <saravanak@google.com>,
        Lukas Wunner <lukas@wunner.de>,
        Jon Hunter <jonathanh@nvidia.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Dmitry Osipenko <digetx@gmail.com>
From:   Marek Szyprowski <m.szyprowski@samsung.com>
Message-ID: <2e1d36f6-338b-e0a1-fbcd-1ea082159bda@samsung.com>
Date:   Tue, 30 Jul 2019 11:56:41 +0200
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References: <CGME20190730092907epcas2p486e986eff88d4b52f707b8cde71fb879@epcas2p4.samsung.com>
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Hi,

On 2019-07-30 11:28, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> After commit 515db266a9da ("driver core: Remove device link creation
> limitation"), if PM-runtime flags are passed to device_link_add(), it
> will fail (returning NULL) due to an overly restrictive flags check
> introduced by that commit.
>
> Fix this issue by extending the check in question to cover the
> PM-runtime flags too.
>
> Fixes: 515db266a9da ("driver core: Remove device link creation limitation")
> Reported-by: Dmitry Osipenko <digetx@gmail.com>
> Tested-by: Jon Hunter <jonathanh@nvidia.com>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

The merged commit also has my 'tested' tags, but I did my tests on v1, 
which worked fine. The offending check has been added in v2 while 
keeping the tags. Thanks for spotting this and fixing the issue, due to 
holidays time, I didn't manage to test v2 before it got merged.

> ---
>   drivers/base/core.c |    6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
>
> Index: linux-pm/drivers/base/core.c
> ===================================================================
> --- linux-pm.orig/drivers/base/core.c
> +++ linux-pm/drivers/base/core.c
> @@ -213,6 +213,9 @@ void device_pm_move_to_tail(struct devic
>   			       DL_FLAG_AUTOREMOVE_SUPPLIER | \
>   			       DL_FLAG_AUTOPROBE_CONSUMER)
>   
> +#define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
> +			    DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
> +
>   /**
>    * device_link_add - Create a link between two devices.
>    * @consumer: Consumer end of the link.
> @@ -274,8 +277,7 @@ struct device_link *device_link_add(stru
>   {
>   	struct device_link *link;
>   
> -	if (!consumer || !supplier ||
> -	    (flags & ~(DL_FLAG_STATELESS | DL_MANAGED_LINK_FLAGS)) ||
> +	if (!consumer || !supplier || flags & ~DL_ADD_VALID_FLAGS ||
>   	    (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
>   	    (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
>   	     flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
>
>
>
>
>
Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland