From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: exynos-drm registration: infinite loop Date: Wed, 5 Nov 2014 15:38:14 +0100 Message-ID: <20141105143813.GA24353@ulmo> References: Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1754922490==" Return-path: Received: from mail-wi0-f173.google.com (mail-wi0-f173.google.com [209.85.212.173]) by gabe.freedesktop.org (Postfix) with ESMTP id 6D2756E7A3 for ; Wed, 5 Nov 2014 06:38:17 -0800 (PST) Received: by mail-wi0-f173.google.com with SMTP id n3so12603809wiv.12 for ; Wed, 05 Nov 2014 06:38:16 -0800 (PST) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: "Matwey V. Kornilov" Cc: kyungmin.park@samsung.com, sw0312.kim@samsung.com, dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org --===============1754922490== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="nFreZHaLTZJo0R7j" Content-Disposition: inline --nFreZHaLTZJo0R7j Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Nov 04, 2014 at 09:18:46PM +0400, Matwey V. Kornilov wrote: > Hi, >=20 > I run 3.18-rc3 kernel on BeagleBone Black. It doesn't have Exynos DRM > of course, but I run multi-platform kernel where CONFIG_DRM_EXYNOS is > set to 'y'. > The issue here is that the platform probe/init goes to infinite loop > as the following: >=20 > [ 5.717343] platform exynos-drm: Driver exynos-drm requests probe defe= rral > [ 5.726848] exynos-drm-ipp exynos-drm-ipp: drm ipp registered successf= ully. > [ 5.734700] platform exynos-drm: Driver exynos-drm requests probe defe= rral > [ 5.744044] exynos-drm-ipp exynos-drm-ipp: drm ipp registered successf= ully. > [ 5.752010] platform exynos-drm: Driver exynos-drm requests probe defe= rral > [ 5.761377] exynos-drm-ipp exynos-drm-ipp: drm ipp registered successf= ully. > [ 5.769291] platform exynos-drm: Driver exynos-drm requests probe defe= rral >=20 > It is quite unexpectable behavior. I would expect that the exynos-drm > failed to initialize with 'no device' error. >=20 > See also for the reference: https://bugzilla.kernel.org/show_bug.cgi?id= =3D87691 The reason for this seems to be that Exynos DRM instantiates a dummy device that it can bind to (see exynos_drm_init()). Now this code is executed unconditonally, so the device will be created whether or not the kernel/module runs on an Exynos SoC. The driver should really bind to some real device rather than instantiating a dummy. Or if it must bind to a dummy then the code needs to at least check that it's running on an Exynos SoC before instantiating the dummy. Thierry --nFreZHaLTZJo0R7j Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJUWjZVAAoJEN0jrNd/PrOhg84P/0e5pYozDIK9vDmu1lL18QDK KTqSVv1s4nGUS+Cqbj/IIsJoRzuxJ4VAHWIK+KRIaXZfmcX8jOg3SdfCQWaOtsTH PyiaSsa5qpwMG8I7uWwjQdHlkxL/3Kt7I5gmLY/UHYl1/8fS9oXiIvtwocdan430 LhiAc9STeNSIKU6sRH3518y3KbNXZCS9sRJoc6Q70ViVvAwf9AJlVOEY2s76UGGo ejCNELNUZt/5A4dKxjvgWS+szDMOMDM0YP2PJe1dxNu71Ypj48A8nd+TL5SActqm 7YxzUVWiD9vA97OmODOFi8sTmpVQwP0XLEXgDiFsqEMDX7CRge5XXNZbpJyXcVND 5vHAQGi5ngLTDi3saKMseInHjrQGVtso1ufTyZjVf4Lgs/1fbesSt6WiKL3EYhm2 Xgt/JBPmGYUNLd2YIooNcssJW/acaiogVIB6e7Ls1+bCUULrVcwRLgOP+M8IUD8M 6f7GXFoolBH0+eiDlQmbcSfferyK7u8xGMjVaBVhb/LjYQaViFmgnFFx+O3SJLpO kodeHro0dPHTECK1Ey5MyTkzDn6IrMffry7Izzbx7f3+5wbq+Tl5CUYcCZxAt+7q zvXm1sBBu74Nw6kC832ewx8QXNpu+udvNExsNu0SWbBggGqmBvXjQ4w2T0UTbAR4 FHjD3RTGvHKZBshJsp2E =D4H2 -----END PGP SIGNATURE----- --nFreZHaLTZJo0R7j-- --===============1754922490== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: inline X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KZHJpLWRldmVs IG1haWxpbmcgbGlzdApkcmktZGV2ZWxAbGlzdHMuZnJlZWRlc2t0b3Aub3JnCmh0dHA6Ly9saXN0 cy5mcmVlZGVza3RvcC5vcmcvbWFpbG1hbi9saXN0aW5mby9kcmktZGV2ZWwK --===============1754922490==--