From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chanwoo Choi Subject: Re: [PATCH v1 2/5] extcon: Return -EPROBE_DEFER when extcon device is not found Date: Wed, 14 Nov 2018 18:48:44 +0900 Message-ID: <5BEBEF7C.7060003@samsung.com> References: <20181110181101.24557-1-andriy.shevchenko@linux.intel.com> <20181110181101.24557-2-andriy.shevchenko@linux.intel.com> <5BE8C821.5080002@samsung.com> <5BEB63C3.1020504@samsung.com> <5BEBE741.6050101@samsung.com> <20181114093652.GK10650@smile.fi.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8BIT Return-path: In-reply-to: <20181114093652.GK10650@smile.fi.intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Andy Shevchenko Cc: MyungJoo Ham , USB , Felipe Balbi , Guenter Roeck , "Krogerus, Heikki" , rogerq@ti.com, Linux PM , "Rafael J. Wysocki" , Sebastian Reichel , Linux OMAP Mailing List , Darren Hart , Platform Driver , Greg Kroah-Hartman , Linux Kernel Mailing List , Chen-Yu Tsai , Hans de Goede List-Id: linux-omap@vger.kernel.org On 2018년 11월 14일 18:36, Andy Shevchenko wrote: > On Wed, Nov 14, 2018 at 06:13:37PM +0900, Chanwoo Choi wrote: >> On 2018년 11월 14일 17:35, Andy Shevchenko wrote: >>> On Wed, Nov 14, 2018 at 1:53 AM Chanwoo Choi wrote: >>> >>>> I was thinking about again to change from NULL to EPROBE_DEFER. >>>> >>>> extcon_get_extcon_dev() function was almost called in the probe function. >>>> But, this function might be called on other position instead of probe. >>> >>> *Might be* sounds like a theoretical thing, care to share what is in you mind? >>> Current users and more important the new coming one are *all* doing the same. >>> >>>> ENODEV is more correct error instead of EPROBE_DEFER. >>> >>> So, you are proposing to continue duplicating conversion from ENODEV >>> to EPROBE_DEFER in *each* caller? >> >> The extcon core don't know the caller situation is in either probe() or other position >> in the caller driver. The caller driver should decide the kind of error value >> by using the return value of extcon_get_extcon_dev(). >> >> extcon_get_extcon_dev() function cannot be modified for only one case. >> If some device driver call extcon_get_extcon_dev() out of probe() fuction, >> EPROBE_DEFER is not always correct. > > I agree with this, but look at the current state of affairs. All users do the same. > If we need to have another case we may consider this later. Because we know the potential wrong case of this change, I can't agree this change. If extcon_get_extcon_dev() returns ENODEV instead of EPROBE_DEFER, it is clear and then there are no problem on both current and future. > > API inside the kernel are not carved in the stone. > > -- Best Regards, Chanwoo Choi Samsung Electronics From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: [v1,2/5] extcon: Return -EPROBE_DEFER when extcon device is not found From: Chanwoo Choi Message-Id: <5BEBEF7C.7060003@samsung.com> Date: Wed, 14 Nov 2018 18:48:44 +0900 To: Andy Shevchenko Cc: MyungJoo Ham , USB , Felipe Balbi , Guenter Roeck , "Krogerus, Heikki" , rogerq@ti.com, Linux PM , "Rafael J. Wysocki" , Sebastian Reichel , Linux OMAP Mailing List , Darren Hart , Platform Driver , Greg Kroah-Hartman , Linux Kernel Mailing List , Chen-Yu Tsai , Hans de Goede List-ID: T24gMjAxOOuFhCAxMeyblCAxNOydvCAxODozNiwgQW5keSBTaGV2Y2hlbmtvIHdyb3RlOgo+IE9u IFdlZCwgTm92IDE0LCAyMDE4IGF0IDA2OjEzOjM3UE0gKzA5MDAsIENoYW53b28gQ2hvaSB3cm90 ZToKPj4gT24gMjAxOOuFhCAxMeyblCAxNOydvCAxNzozNSwgQW5keSBTaGV2Y2hlbmtvIHdyb3Rl Ogo+Pj4gT24gV2VkLCBOb3YgMTQsIDIwMTggYXQgMTo1MyBBTSBDaGFud29vIENob2kgPGN3MDAu Y2hvaUBzYW1zdW5nLmNvbT4gd3JvdGU6Cj4+Pgo+Pj4+IEkgd2FzIHRoaW5raW5nIGFib3V0IGFn YWluIHRvIGNoYW5nZSBmcm9tIE5VTEwgdG8gRVBST0JFX0RFRkVSLgo+Pj4+Cj4+Pj4gZXh0Y29u X2dldF9leHRjb25fZGV2KCkgZnVuY3Rpb24gd2FzIGFsbW9zdCBjYWxsZWQgaW4gdGhlIHByb2Jl IGZ1bmN0aW9uLgo+Pj4+IEJ1dCwgdGhpcyBmdW5jdGlvbiBtaWdodCBiZSBjYWxsZWQgb24gb3Ro ZXIgcG9zaXRpb24gaW5zdGVhZCBvZiBwcm9iZS4KPj4+Cj4+PiAqTWlnaHQgYmUqIHNvdW5kcyBs aWtlIGEgdGhlb3JldGljYWwgdGhpbmcsIGNhcmUgdG8gc2hhcmUgd2hhdCBpcyBpbiB5b3UgbWlu ZD8KPj4+IEN1cnJlbnQgdXNlcnMgYW5kIG1vcmUgaW1wb3J0YW50IHRoZSBuZXcgY29taW5nIG9u ZSBhcmUgKmFsbCogZG9pbmcgdGhlIHNhbWUuCj4+Pgo+Pj4+IEVOT0RFViBpcyBtb3JlIGNvcnJl Y3QgZXJyb3IgaW5zdGVhZCBvZiBFUFJPQkVfREVGRVIuCj4+Pgo+Pj4gU28sIHlvdSBhcmUgcHJv cG9zaW5nIHRvIGNvbnRpbnVlIGR1cGxpY2F0aW5nIGNvbnZlcnNpb24gZnJvbSBFTk9ERVYKPj4+ IHRvIEVQUk9CRV9ERUZFUiBpbiAqZWFjaCogY2FsbGVyPwo+Pgo+PiBUaGUgZXh0Y29uIGNvcmUg ZG9uJ3Qga25vdyB0aGUgY2FsbGVyIHNpdHVhdGlvbiBpcyBpbiBlaXRoZXIgcHJvYmUoKSBvciBv dGhlciBwb3NpdGlvbgo+PiBpbiB0aGUgY2FsbGVyIGRyaXZlci4gVGhlIGNhbGxlciBkcml2ZXIg c2hvdWxkIGRlY2lkZSB0aGUga2luZCBvZiBlcnJvciB2YWx1ZQo+PiBieSB1c2luZyB0aGUgcmV0 dXJuIHZhbHVlIG9mIGV4dGNvbl9nZXRfZXh0Y29uX2RldigpLgo+Pgo+PiBleHRjb25fZ2V0X2V4 dGNvbl9kZXYoKSBmdW5jdGlvbiBjYW5ub3QgYmUgbW9kaWZpZWQgZm9yIG9ubHkgb25lIGNhc2Uu Cj4+IElmIHNvbWUgZGV2aWNlIGRyaXZlciBjYWxsIGV4dGNvbl9nZXRfZXh0Y29uX2RldigpIG91 dCBvZiBwcm9iZSgpIGZ1Y3Rpb24sCj4+IEVQUk9CRV9ERUZFUiBpcyBub3QgYWx3YXlzIGNvcnJl Y3QuCj4gCj4gSSBhZ3JlZSB3aXRoIHRoaXMsIGJ1dCBsb29rIGF0IHRoZSBjdXJyZW50IHN0YXRl IG9mIGFmZmFpcnMuIEFsbCB1c2VycyBkbyB0aGUgc2FtZS4KPiBJZiB3ZSBuZWVkIHRvIGhhdmUg YW5vdGhlciBjYXNlIHdlIG1heSBjb25zaWRlciB0aGlzIGxhdGVyLgoKQmVjYXVzZSB3ZSBrbm93 IHRoZSBwb3RlbnRpYWwgd3JvbmcgY2FzZSBvZiB0aGlzIGNoYW5nZSwgSSBjYW4ndCBhZ3JlZSB0 aGlzIGNoYW5nZS4KSWYgZXh0Y29uX2dldF9leHRjb25fZGV2KCkgcmV0dXJucyBFTk9ERVYgaW5z dGVhZCBvZiBFUFJPQkVfREVGRVIsCml0IGlzIGNsZWFyIGFuZCB0aGVuIHRoZXJlIGFyZSBubyBw cm9ibGVtIG9uIGJvdGggY3VycmVudCBhbmQgZnV0dXJlLgoKPiAKPiBBUEkgaW5zaWRlIHRoZSBr ZXJuZWwgYXJlIG5vdCBjYXJ2ZWQgaW4gdGhlIHN0b25lLgo+IAo+Cg==