From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH v1] drm/modes: Skip invalid cmdline mode Date: Thu, 11 Jul 2019 11:03:27 +0200 Message-ID: <20190711090327.keuxt2ztfqecdbef@flea> References: <20190709145151.23086-1-digetx@gmail.com> <20190710101229.54ufuhmh22dfxclr@flea> <4ad69d15-07f8-9753-72d6-a51402c94c20@gmail.com> <20190710125552.qvmnh6qs63ikiu2k@flea> <20190710130615.gvi2jwgr2cds66xr@flea> <75719cad-c65c-7ebc-3ea8-98134f86ddc3@gmail.com> <4a13f12f-05a7-473e-4e4e-7a7e32d09720@gmail.com> <20190710140504.t5lsk36gnn5cdn6b@flea> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1623689401==" 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: Dmitry Osipenko Cc: David Airlie , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Jonathan Hunter , Thierry Reding , linux-tegra@vger.kernel.org, Sean Paul List-Id: linux-tegra@vger.kernel.org --===============1623689401== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="f3d53ks7a7blbuls" Content-Disposition: inline --f3d53ks7a7blbuls Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Jul 10, 2019 at 06:05:18PM +0300, Dmitry Osipenko wrote: > 10.07.2019 17:05, Maxime Ripard =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > > On Wed, Jul 10, 2019 at 04:29:19PM +0300, Dmitry Osipenko wrote: > >> This works: > >> > >> diff --git a/drivers/gpu/drm/drm_client_modeset.c b/drivers/gpu/drm/dr= m_client_modeset.c > >> index 56d36779d213..e5a2f9c8f404 100644 > >> --- a/drivers/gpu/drm/drm_client_modeset.c > >> +++ b/drivers/gpu/drm/drm_client_modeset.c > >> @@ -182,6 +182,8 @@ drm_connector_pick_cmdline_mode(struct drm_connect= or *connector) > >> mode =3D drm_mode_create_from_cmdline_mode(connector->dev, cmd= line_mode); > >> if (mode) > >> list_add(&mode->head, &connector->modes); > >> + else > >> + cmdline_mode->specified =3D false; > > > > Hmmm, it's not clear to me why that wouldn't be the case. > > > > If we come back to the beginning of that function, we retrieve the > > cmdline_mode buffer from the connector pointer, that will probably > > have been parsed a first time using drm_mode_create_from_cmdline_mode > > in drm_helper_probe_add_cmdline_mode. > > > > Now, I'm guessing that the issue is that in > > drm_mode_parse_command_line_for_connector, if we have a named mode, we > > just copy the mode over and set mode->specified. > > > > And we then move over to do other checks, and that's probably what > > fails and returns, but our drm_cmdline_mode will have been modified. > > > > I'm not entirely sure how to deal with that though. > > > > I guess we could allocate a drm_cmdline_mode structure on the stack, > > fill that, and if successful copy over its content to the one in > > drm_connector. That would allow us to only change the content on > > success, which is what I would expect from such a function? > > > > How does that sound? > > I now see that there is DRM_MODE_TYPE_USERDEF flag that is assigned only > for the "cmdline" mode and drm_client_rotation() is the only place in > DRM code that cares about whether mode is from cmdline, hence looks like > it will be more correct to do the following: I'm still under the impression that we're dealing with workarounds of a more central issue, which is that we shouldn't return a partially modified drm_cmdline_mode. You said it yourself, the breakage is in the commit changing the command line parsing logic, while you're fixing here some code that was introduced later on. Can you try the followintg patch? http://code.bulix.org/8cwk4c-794565?raw Thanks! Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com --f3d53ks7a7blbuls Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRcEzekXsqa64kGDp7j7w1vZxhRxQUCXSb7XwAKCRDj7w1vZxhR xX+CAP9sjZiZGMMVxtQslRFZ2ds6qiU8zvuED+tZbBt9xUrxUQEAxkw0kkGu/uqe 91WJFWA4MRVpsCZ6/zKJ+XSj09iFcQk= =+Zlg -----END PGP SIGNATURE----- --f3d53ks7a7blbuls-- --===============1623689401== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: inline X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KZHJpLWRldmVs IG1haWxpbmcgbGlzdApkcmktZGV2ZWxAbGlzdHMuZnJlZWRlc2t0b3Aub3JnCmh0dHBzOi8vbGlz dHMuZnJlZWRlc2t0b3Aub3JnL21haWxtYW4vbGlzdGluZm8vZHJpLWRldmVs --===============1623689401==--