On Wed, Jan 8, 2020 at 11:08 AM Sam Ravnborg <sam@xxxxxxxxxxxx> wrote: > On Wed, Jan 08, 2020 at 11:55:29AM +0200, Jani Nikula wrote: > > On Tue, 07 Jan 2020, Arnd Bergmann <arnd@xxxxxxxx> wrote: > > > Making this IS_REACHABLE() was still wrong, as that just determines > > > whether the lower-level backlight code would be reachable from the panel > > > driver. However, with CONFIG_DRM=y and CONFIG_BACKLIGHT_CLASS_DEVICE=m, > > > the drm_panel_of_backlight is left out of drm_panel.o but the condition > > > tells the driver that it is there, leading to multiple link errors such as > > > > > > ERROR: "drm_panel_of_backlight" [drivers/gpu/drm/panel/panel-sitronix-st7701.ko] undefined! > > > ERROR: "drm_panel_of_backlight" [drivers/gpu/drm/panel/panel-sharp-ls043t1le01.ko] undefined! > > > ERROR: "drm_panel_of_backlight" [drivers/gpu/drm/panel/panel-seiko-43wvf1g.ko] undefined! > > > ERROR: "drm_panel_of_backlight" [drivers/gpu/drm/panel/panel-ronbo-rb070d30.ko] undefined! > > > ERROR: "drm_panel_of_backlight" [drivers/gpu/drm/panel/panel-rocktech-jh057n00900.ko] undefined! > > > ERROR: "drm_panel_of_backlight" [drivers/gpu/drm/panel/panel-panasonic-vvx10f034n00.ko] undefined! > > > ERROR: "drm_panel_of_backlight" [drivers/gpu/drm/panel/panel-osd-osd101t2587-53ts.ko] undefined! > > > > > > Change the condition to check for whether the function was actually part > > > of the drm module. This version of the patch survived a few hundred > > > randconfig builds, so I have a good feeling this might be the last > > > one for the export. > > > > Broken record, this will still be wrong, even if it builds and links. No > > backlight support for panel despite expectations. > > > > See http://mid.mail-archive.com/87d0cnynst.fsf@xxxxxxxxx > > > > All of this is just another hack until the backlight config usage is > > fixed for good. Do we really want to make this the example to copy paste > > wherever we hit the issue next? > > > > I'm not naking, but I'm not acking either. > > I will try to take a look at your old BACKLIGHT_CLASS_DEVICE patch this > weekend. I think we need that one fixed - and then we can have this mess > with "drm_panel_of_backlight" fixed in the right way. I had also attempted to fix the larger mess around 'select' statements in DRM/FB around BACKLIGHT_CLASS_DEVICE several times in the past, and even at some point sent a patch that was acked but never merged and later broke because of other changes. If there is a new approach, I'm happy to add patches to my randconfig builder and see if there are regressions in some corner cases. Arnd _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
