On Fri, Jul 12, 2019 at 11:30:01AM +0300, Dmitry Osipenko wrote: > 12.07.2019 11:10, Maxime Ripard пишет: > > On Thu, Jul 11, 2019 at 06:55:03PM +0300, Dmitry Osipenko wrote: > >> 11.07.2019 12:03, Maxime Ripard пишет: > >>> On Wed, Jul 10, 2019 at 06:05:18PM +0300, Dmitry Osipenko wrote: > >>>> 10.07.2019 17:05, Maxime Ripard пишет: > >>>>> 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/drm_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_connector *connector) > >>>>>> mode = drm_mode_create_from_cmdline_mode(connector->dev, cmdline_mode); > >>>>>> if (mode) > >>>>>> list_add(&mode->head, &connector->modes); > >>>>>> + else > >>>>>> + cmdline_mode->specified = 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. > >> > >> The problem stems from assumption that *any* named mode is valid. It > >> looks to me that the ultimate solution would be to move the mode's name > >> comparison into the [1], if that's possible. > >> > >> [1] drm_mode_parse_command_line_for_connector() > > > > Well, one could argue that video=tegrafb is invalid and should be > > rejected as well, but we haven't cleared that up. > > The video=tegrafb is invalid mode, there is nothing to argue here. And > the problem is that invalid modes and not rejected for the very beginning. Yeah, I guess fb_get_options should also return an error in such a case, but I'm a bit worried about the side effects here. > >>> Can you try the followintg patch? > >>> http://code.bulix.org/8cwk4c-794565?raw > >> > >> This doesn't help because the problem with the rotation_reflection is > >> that it's 0 if "rotation" not present in the cmdline and then ilog2(0) > >> returns -1. So the patch "drm/modes: Don't apply cmdline's rotation if > >> it wasn't specified" should be correct in any case. > > > > So we would have the same issue with rotate=0 then? > > No, we won't. Rotation mode is parsed into the DRM_MODE bitmask and > rotate=0 corresponds to DRM_MODE_ROTATE_0, which is BIT(0) as you may > notice. Hence rotation_reflection=0 is always an invalid value, meaning > that "rotate" option does not present in the cmdline. Please consult the > code, in particular see drm_mode_parse_cmdline_options() which was > written by yourself ;) Sigh... You're right :) Sorry for that, I'll reply to the other patch Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
