From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [PATCH] usb: xhci: remove the code build warning Date: Tue, 5 Jun 2018 11:06:06 +0200 Message-ID: <20180605090606.GA20649@ulmo> References: <1528216500-14172-1-git-send-email-gengdongjiu@huawei.com> <20180605084019.GA8665@kroah.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="qDbXVdCdHGoSgWSk" Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: gengdongjiu Cc: Greg KH , mathias.nyman@intel.com, jonathanh@nvidia.com, linux-usb@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-tegra@vger.kernel.org --qDbXVdCdHGoSgWSk Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jun 05, 2018 at 04:54:17PM +0800, gengdongjiu wrote: >=20 >=20 > On 2018/6/5 16:40, Greg KH wrote: > > On Wed, Jun 06, 2018 at 12:35:00AM +0800, Dongjiu Geng wrote: > >> Initialize the 'err' variate to remove the build warning, > >> the warning is shown as below: > >> > >> drivers/usb/host/xhci-tegra.c: In function =E2=80=98tegra_xusb_mbox_th= read=E2=80=99: > >> drivers/usb/host/xhci-tegra.c:552:6: warning: =E2=80=98err=E2=80=99 ma= y be used uninitialized in this function [-Wuninitialized] > >> drivers/usb/host/xhci-tegra.c:482:6: note: =E2=80=98err=E2=80=99 was d= eclared here > >> > >> Signed-off-by: Dongjiu Geng > >> --- > >=20 > > Any hint as to what commit caused this warning to show up? >=20 > It seems below commit: >=20 > commit e84fce0f8837496a48d11086829bdbe170358b7a > Author: Thierry Reding > Date: Thu Feb 11 18:10:48 2016 +0100 >=20 > usb: xhci: Add NVIDIA Tegra XUSB controller driver >=20 > Add support for the on-chip XUSB controller present on Tegra SoCs. Th= is > controller, when loaded with external firmware, exposes an interface > compliant with xHCI. This driver loads the firmware, starts the > controller, and is able to service host-specific messages sent by the > controller's firmware. >=20 > The controller also supports USB device mode as well as powergating > of the SuperSpeed and host-controller logic when not in use, but > support for these is not yet implemented. >=20 > Based on work by: > Ajay Gupta > Bharath Yadav > Andrew Bresticker >=20 > Cc: Mathias Nyman > Cc: Greg Kroah-Hartman > Acked-by: Mathias Nyman > Signed-off-by: Thierry Reding I've never seen this warning before. It's also a false positive in that technically the mailbox message will always have at least one bit set in "mask". However, I don't see how the compiler could know about it, given that the data comes from an external source, so I think this makes sense as a hint to the compiler. So: Acked-by: Thierry Reding Can you provide more detail on what exact version of which compiler you used that triggered this? I wonder why it's never presented itself with the compiler that I use. Thierry --qDbXVdCdHGoSgWSk Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEiOrDCAFJzPfAjcif3SOs138+s6EFAlsWUnsACgkQ3SOs138+ s6Gg1A/6A7nFC4EyLNBlNi2EAo5oSBhXA4/i4b+HkR1LHHtteuQH3so3HUavC7Gm J8Pz46KMAXZmEW2fMfT+Kfqh6Cs8+3xx9grJ2XMASV1kSdYzbYMwNIiEidvD006Y d1nvdrRSnFvWytGtsykpY9coCrNlA8t41OkbtR73l9UDN5ETGqsNxujc3sT7stZT eqMoIlIqOcwVRKPDv3Tgm88iTawc0NuMcfLqCd7dI7netkOV51yIVTs5baDFHL/7 iYl7l1FdIa1wMi6bWs0TSFQZilYoj2i4ADffRvhgTVU0zAjmWFOre2yPPBlCT9z8 FIG1FfLzS9TT7bgMkCp/BTk7XBBcMHPUM0AheqSxYPq+juIp0Ia2Z4dnmxyPPc3f jvkEWHRgXMENRkitMtUV4lTVmVCjDJwLZRdmWIc4S5A/E9nJMuwnWdIDSRPZXVsY 3XR8pt1AWMBF9unPsaxW3X+IsaMgYoD4vJZ/LWtgO+l8p5+AqCeoYobSmNyU3nlc PgogrW2Lxg/Nd8jrHl4LbGw/7rSLnt6UK85E0afLbIPQtkEwg7uAvhQpC+Q04Lxh +WXj0Iv1dt9oYXSyXrfUcMMMVf2tDHcinXdk8F55Exojp4Wm7vD/RKjI90+RAmvR d/Mvex80nrxGL8XTeDjJhGfiExQBbNf7fJfMhCdn5w9xFrxqc6U= =GnaC -----END PGP SIGNATURE----- --qDbXVdCdHGoSgWSk-- 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: usb: xhci: remove the code build warning From: Thierry Reding Message-Id: <20180605090606.GA20649@ulmo> Date: Tue, 5 Jun 2018 11:06:06 +0200 To: gengdongjiu Cc: Greg KH , mathias.nyman@intel.com, jonathanh@nvidia.com, linux-usb@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org List-ID: T24gVHVlLCBKdW4gMDUsIDIwMTggYXQgMDQ6NTQ6MTdQTSArMDgwMCwgZ2VuZ2RvbmdqaXUgd3Jv dGU6Cj4gCj4gCj4gT24gMjAxOC82LzUgMTY6NDAsIEdyZWcgS0ggd3JvdGU6Cj4gPiBPbiBXZWQs IEp1biAwNiwgMjAxOCBhdCAxMjozNTowMEFNICswODAwLCBEb25naml1IEdlbmcgd3JvdGU6Cj4g Pj4gSW5pdGlhbGl6ZSB0aGUgJ2VycicgdmFyaWF0ZSB0byByZW1vdmUgdGhlIGJ1aWxkIHdhcm5p bmcsCj4gPj4gdGhlIHdhcm5pbmcgaXMgc2hvd24gYXMgYmVsb3c6Cj4gPj4KPiA+PiBkcml2ZXJz L3VzYi9ob3N0L3hoY2ktdGVncmEuYzogSW4gZnVuY3Rpb24g4oCYdGVncmFfeHVzYl9tYm94X3Ro cmVhZOKAmToKPiA+PiBkcml2ZXJzL3VzYi9ob3N0L3hoY2ktdGVncmEuYzo1NTI6Njogd2Fybmlu Zzog4oCYZXJy4oCZIG1heSBiZSB1c2VkIHVuaW5pdGlhbGl6ZWQgaW4gdGhpcyBmdW5jdGlvbiBb LVd1bmluaXRpYWxpemVkXQo+ID4+IGRyaXZlcnMvdXNiL2hvc3QveGhjaS10ZWdyYS5jOjQ4Mjo2 OiBub3RlOiDigJhlcnLigJkgd2FzIGRlY2xhcmVkIGhlcmUKPiA+Pgo+ID4+IFNpZ25lZC1vZmYt Ynk6IERvbmdqaXUgR2VuZyA8Z2VuZ2RvbmdqaXVAaHVhd2VpLmNvbT4KPiA+PiAtLS0KPiA+IAo+ ID4gQW55IGhpbnQgYXMgdG8gd2hhdCBjb21taXQgY2F1c2VkIHRoaXMgd2FybmluZyB0byBzaG93 IHVwPwo+IAo+IEl0IHNlZW1zIGJlbG93IGNvbW1pdDoKPiAKPiBjb21taXQgZTg0ZmNlMGY4ODM3 NDk2YTQ4ZDExMDg2ODI5YmRiZTE3MDM1OGI3YQo+IEF1dGhvcjogVGhpZXJyeSBSZWRpbmcgPHRy ZWRpbmdAbnZpZGlhLmNvbT4KPiBEYXRlOiAgIFRodSBGZWIgMTEgMTg6MTA6NDggMjAxNiArMDEw MAo+IAo+ICAgICB1c2I6IHhoY2k6IEFkZCBOVklESUEgVGVncmEgWFVTQiBjb250cm9sbGVyIGRy aXZlcgo+IAo+ICAgICBBZGQgc3VwcG9ydCBmb3IgdGhlIG9uLWNoaXAgWFVTQiBjb250cm9sbGVy IHByZXNlbnQgb24gVGVncmEgU29Dcy4gVGhpcwo+ICAgICBjb250cm9sbGVyLCB3aGVuIGxvYWRl ZCB3aXRoIGV4dGVybmFsIGZpcm13YXJlLCBleHBvc2VzIGFuIGludGVyZmFjZQo+ICAgICBjb21w bGlhbnQgd2l0aCB4SENJLiBUaGlzIGRyaXZlciBsb2FkcyB0aGUgZmlybXdhcmUsIHN0YXJ0cyB0 aGUKPiAgICAgY29udHJvbGxlciwgYW5kIGlzIGFibGUgdG8gc2VydmljZSBob3N0LXNwZWNpZmlj IG1lc3NhZ2VzIHNlbnQgYnkgdGhlCj4gICAgIGNvbnRyb2xsZXIncyBmaXJtd2FyZS4KPiAKPiAg ICAgVGhlIGNvbnRyb2xsZXIgYWxzbyBzdXBwb3J0cyBVU0IgZGV2aWNlIG1vZGUgYXMgd2VsbCBh cyBwb3dlcmdhdGluZwo+ICAgICBvZiB0aGUgU3VwZXJTcGVlZCBhbmQgaG9zdC1jb250cm9sbGVy IGxvZ2ljIHdoZW4gbm90IGluIHVzZSwgYnV0Cj4gICAgIHN1cHBvcnQgZm9yIHRoZXNlIGlzIG5v dCB5ZXQgaW1wbGVtZW50ZWQuCj4gCj4gICAgIEJhc2VkIG9uIHdvcmsgYnk6Cj4gICAgICAgQWph eSBHdXB0YSA8YWpheWdAbnZpZGlhLmNvbT4KPiAgICAgICBCaGFyYXRoIFlhZGF2IDxieWFkYXZA bnZpZGlhLmNvbT4KPiAgICAgICBBbmRyZXcgQnJlc3RpY2tlciA8YWJyZXN0aWNAY2hyb21pdW0u b3JnPgo+IAo+ICAgICBDYzogTWF0aGlhcyBOeW1hbiA8bWF0aGlhcy5ueW1hbkBpbnRlbC5jb20+ Cj4gICAgIENjOiBHcmVnIEtyb2FoLUhhcnRtYW4gPGdyZWdraEBsaW51eGZvdW5kYXRpb24ub3Jn Pgo+ICAgICBBY2tlZC1ieTogTWF0aGlhcyBOeW1hbiA8bWF0aGlhcy5ueW1hbkBsaW51eC5pbnRl bC5jb20+Cj4gICAgIFNpZ25lZC1vZmYtYnk6IFRoaWVycnkgUmVkaW5nIDx0cmVkaW5nQG52aWRp YS5jb20+CgpJJ3ZlIG5ldmVyIHNlZW4gdGhpcyB3YXJuaW5nIGJlZm9yZS4gSXQncyBhbHNvIGEg ZmFsc2UgcG9zaXRpdmUgaW4gdGhhdAp0ZWNobmljYWxseSB0aGUgbWFpbGJveCBtZXNzYWdlIHdp bGwgYWx3YXlzIGhhdmUgYXQgbGVhc3Qgb25lIGJpdCBzZXQgaW4KIm1hc2siLiBIb3dldmVyLCBJ IGRvbid0IHNlZSBob3cgdGhlIGNvbXBpbGVyIGNvdWxkIGtub3cgYWJvdXQgaXQsIGdpdmVuCnRo YXQgdGhlIGRhdGEgY29tZXMgZnJvbSBhbiBleHRlcm5hbCBzb3VyY2UsIHNvIEkgdGhpbmsgdGhp cyBtYWtlcyBzZW5zZQphcyBhIGhpbnQgdG8gdGhlIGNvbXBpbGVyLiBTbzoKCkFja2VkLWJ5OiBU aGllcnJ5IFJlZGluZyA8dHJlZGluZ0BudmlkaWEuY29tPgoKQ2FuIHlvdSBwcm92aWRlIG1vcmUg ZGV0YWlsIG9uIHdoYXQgZXhhY3QgdmVyc2lvbiBvZiB3aGljaCBjb21waWxlciB5b3UKdXNlZCB0 aGF0IHRyaWdnZXJlZCB0aGlzPyBJIHdvbmRlciB3aHkgaXQncyBuZXZlciBwcmVzZW50ZWQgaXRz ZWxmIHdpdGgKdGhlIGNvbXBpbGVyIHRoYXQgSSB1c2UuCgpUaGllcnJ5Cg==