From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [PATCH] drm/nouveau: tegra: Initialize mode configuration Date: Wed, 7 Nov 2018 17:12:27 +0100 Message-ID: <20181107161227.GA6664@ulmo> References: <20181106162415.3578-1-thierry.reding@gmail.com> <20181106164122.GB9144@intel.com> <20181107153409.GA7155@ulmo> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1947878648==" Return-path: 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: Ilia Mirkin Cc: linux-tegra@vger.kernel.org, nouveau , dri-devel , Ben Skeggs List-Id: linux-tegra@vger.kernel.org --===============1947878648== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="45Z9DzgjV8m4Oswq" Content-Disposition: inline --45Z9DzgjV8m4Oswq Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Nov 07, 2018 at 10:52:11AM -0500, Ilia Mirkin wrote: > On Wed, Nov 7, 2018 at 10:34 AM Thierry Reding = wrote: > > > > On Tue, Nov 06, 2018 at 06:41:22PM +0200, Ville Syrj=C3=A4l=C3=A4 wrote: > > > On Tue, Nov 06, 2018 at 05:24:15PM +0100, Thierry Reding wrote: > > > > From: Thierry Reding > > > > > > > > Irrespective of whether or not the device has any usable outputs, t= he > > > > modesetting helpers will try to register all the resources such as = CRTCs > > > > and planes. Unfortunately, the helpers rely on drm_mode_config_init= () to > > > > properly set up internal data structures. Since the Tegra GPU does = not > > > > have a display engine, the Nouveau driver doesn't set this up for T= egra, > > > > which results in the following oops on driver probe: > > > > > > Remove DRIVER_MODESET ? > > > > Yeah, that works as well. Technically I suppose somebody could be > > instantiating the IP in an SoC and include a display engine, in which > > case we'd need the DRIVER_MODESET feature again, but I'm not aware of > > anyone doing that, so it may not be worth planning for that at this > > point. >=20 > I thought DRIVER_MODESET was required even for rendernodes. Is that no > longer the case? Indeed. Removing the DRIVER_MODESET feature gets the driver to load properly, but trying to actually use Nouveau (e.g. kmscube) crashes in other places. Now that you mention it, I vaguely remember trying to do something similar a long time ago and I had to split up DRIVER_MODESET into more fine-grained features (basically DRIVER_MODESET and DRIVER_LEGACY, if I remember correctly) to avoid crashes. But this must have been three or four years ago and I can't recall the exact details. > Note that e.g. GF117 GPUs also don't have a display engine hooked up > in nouveau (or in hardware). That's interesting. I think there'd be some symmetric elegance to it if the PCI driver supported DRIVER_MODESET irrespective of the feature set of the card and if the platform driver did the same. In the end, this isn't really a driver-specific feature, but a device-specific feature. Or to put it another way: the driver inherently supports modesetting features, irrespective of a device's specific capabilities. Thierry --45Z9DzgjV8m4Oswq Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEiOrDCAFJzPfAjcif3SOs138+s6EFAlvjDukACgkQ3SOs138+ s6E+8RAAqeB2WBy0vMJMwcBf6YZmPm6f6we1gcRyoiZ9YpPGwH+pQzAUB4qGW1NO pb1IIwa92LQt/zn5+bjlkX9jBWzNGQDF354vMruiPlPeO47Ix3dslEAikg6OO9gq 3DtbFzYmNDabk4gmhau/Yf1fr5Se8qTkX9p5L4xDLzRFNgv1EK8HW6jf26yupMYK oeTs74/bDl4qau0Areh80md/dgZTGN3YdakKxOlH1ea8qFrHw6CuJKhW6PiafPcS sZKDdlwkBJiBPYmPn9FRTKpXd9Oa8HpYHQqboO6/OFJCP7z1ZmGcrC8QsHgXHt5o v8qgAzweJtOs+EOSu1QLveBeRt4FI+vq2Ky53bT3ZIos2NNjz2aedNSPmtxczWAx LPDs/IEWI7ROTQQxQ+Uuah8Aqbvkx/OKg4qhDqtEkeFvCA64sEc2Zi4grt5pZ6yf fIUElVu3ocxKJxJPlFEJgrkvKfWrNmOqXxnGSkevq87hrjFHhEn0KHg4VfEqee4B UX53oTGBnamso4BCXUhOuJu9iQol53vKhYYAipF+IV+lGzZE0gTPhYS/kjo5rSbH G1AZUcbe3cfiOUnQeJ1ip57vnm4zUThABTcTEoE7gGldpORVZ4ABCdfGtpKtb3Q4 +pS+uy1YhafUn7/8Wuo3FPyFDvvpP2SSLVNbaQFn+tW3ZEKE2tY= =5m+B -----END PGP SIGNATURE----- --45Z9DzgjV8m4Oswq-- --===============1947878648== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: inline X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KZHJpLWRldmVs IG1haWxpbmcgbGlzdApkcmktZGV2ZWxAbGlzdHMuZnJlZWRlc2t0b3Aub3JnCmh0dHBzOi8vbGlz dHMuZnJlZWRlc2t0b3Aub3JnL21haWxtYW4vbGlzdGluZm8vZHJpLWRldmVsCg== --===============1947878648==--