12.07.2019 22:53, Maxime Ripard пишет: > 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.
At least the showstopper regression is fixed now. Everything else could be worked out later on. >>>>> 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 Thank you very much.
