From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-kernel@vger.kernel.org,
Saravana Kannan <saravanak@google.com>,
linux-acpi@vger.kernel.org,
"Rafael J. Wysocki" <rafael@kernel.org>,
Ferry Toth <fntoth@gmail.com>
Subject: Re: [PATCH v1 1/2] device property: Keep secondary firmware node secondary by type
Date: Fri, 23 Oct 2020 15:34:12 +0300 [thread overview]
Message-ID: <20201023123412.GA614478@kuha.fi.intel.com> (raw)
In-Reply-To: <20201022184100.71659-1-andriy.shevchenko@linux.intel.com>
On Thu, Oct 22, 2020 at 09:40:59PM +0300, Andy Shevchenko wrote:
> Behind primary and secondary we understand the type of the nodes
> which might define their ordering. However, if primary node gone,
> we can't maintain the ordering by definition of the linked list.
> Thus, by ordering secondary node becomes first in the list.
> But in this case the meaning of it is still secondary (or auxiliary).
> The type of the node is maintained by the secondary pointer in it:
>
> secondary pointer Meaning
> NULL or valid primary node
> ERR_PTR(-ENODEV) secondary node
>
> So, if by some reason we do the following sequence of calls
>
> set_primary_fwnode(dev, NULL);
> set_primary_fwnode(dev, primary);
>
> we should preserve secondary node.
>
> This concept is supported by the description of set_primary_fwnode()
> along with implementation of set_secondary_fwnode(). Hence, fix
> the commit c15e1bdda436 to follow this as well.
>
> Fixes: c15e1bdda436 ("device property: Fix the secondary firmware node handling in set_primary_fwnode()")
> Cc: Ferry Toth <fntoth@gmail.com>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
FWIW:
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> ---
> drivers/base/core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index c852f16c111b..41feab679fa1 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -4278,7 +4278,7 @@ void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
> } else {
> if (fwnode_is_primary(fn)) {
> dev->fwnode = fn->secondary;
> - fn->secondary = NULL;
> + fn->secondary = ERR_PTR(-ENODEV);
> } else {
> dev->fwnode = NULL;
> }
> --
> 2.28.0
--
heikki
next prev parent reply other threads:[~2020-10-23 12:34 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-22 18:40 [PATCH v1 1/2] device property: Keep secondary firmware node secondary by type Andy Shevchenko
2020-10-22 18:41 ` [PATCH v1 2/2] device property: Don't clear secondary pointer for shared primary firmware node Andy Shevchenko
2020-10-23 12:35 ` Heikki Krogerus
2020-10-23 14:03 ` Ferry Toth
2020-10-23 14:16 ` Ferry Toth
2020-10-23 12:34 ` Heikki Krogerus [this message]
2020-10-23 14:16 ` [PATCH v1 1/2] device property: Keep secondary firmware node secondary by type Ferry Toth
[not found] ` <ef59c911-8d8b-783a-c756-05123f428302@gmail.com>
2020-10-23 14:19 ` Andy Shevchenko
2020-10-27 18:21 ` Rafael J. Wysocki
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