From mboxrd@z Thu Jan 1 00:00:00 1970 From: Petr Mladek Subject: Re: [PATCH 5/5] lib/vsprintf: Add %pfw conversion specifier for printing fwnode names Date: Thu, 28 Mar 2019 15:35:39 +0100 Message-ID: <20190328143539.nty4xzwnml47vcj2@pathway.suse.cz> References: <20190322152930.16642-1-sakari.ailus@linux.intel.com> <20190322152930.16642-6-sakari.ailus@linux.intel.com> <20190326151307.erqyps6wfvf4on2d@pathway.suse.cz> <20190327141047.bhndwqde7vjz6bad@paasikivi.fi.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20190327141047.bhndwqde7vjz6bad@paasikivi.fi.intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Sakari Ailus Cc: linux-kernel@vger.kernel.org, rafael@kernel.org, Andy Shevchenko , linux-acpi@vger.kernel.org, devicetree@vger.kernel.org List-Id: linux-acpi@vger.kernel.org On Wed 2019-03-27 16:10:48, Sakari Ailus wrote: > Hi Petr, > > On Tue, Mar 26, 2019 at 04:13:07PM +0100, Petr Mladek wrote: > > On Fri 2019-03-22 17:29:30, Sakari Ailus wrote: > > > Add support for %pfw conversion specifier (with "f" and "P" modifiers) to > > > support printing full path of the node, including its name ("f") and only > > > the node's name ("P") in the printk family of functions. The two flags > > > have equivalent functionality to existing %pOF with the same two modifiers > > > ("f" and "P") on OF based systems. The ability to do the same on ACPI > > > based systems is added by this patch. > > > > > > On ACPI based systems the resulting strings look like > > > > > > \_SB.PCI0.CIO2.port@1.endpoint@0 > > > > > > where the nodes are separated by a dot (".") and the first three are > > > ACPI device nodes and the latter two ACPI data nodes. > > > > > > Depends-on: ("vsprintf: Remove support for %pF and %pf in favour of %pS and %ps") > > > > Reusing obsolete modifiers is dangerous from many reasons: > > > > + people might miss the change of the meaning > > + backporting mistakes > > + 3rd party modules > > > > It might be acceptable if the long term gain is bigger > > than a short time difficulties. But it would be better > > to it a safe way when possible. > > > > Fortunately, we could keep the backward compatibility > > for "%pf" and handle only "%pfw*" with the fwnode api. > > The v2 of this patch produces a warning (using WARN_ONCE()) for "%pf" not > immediately followed by "w". "%pfw" was not a valid conversion specifier > before this set, so we're actually not re-using the exactly same conversion > specifiers. I see. I would keep the two patchsets separate. I mean that this patchset should expect that the original handling of %pf is still there. The way how to remove or obsolete "%pf" should be handled in the patchset removing all %pf users or it can be done in a completely separate patch. The conflict can get handled when merging the two patchsets. Best Regards, Petr