Kconfig says fbcon is required by drm_kms_helper. If radeon, fbcon, and drm_kms_helper are all modules, radeon is auto loaded (by PCI id?), drm_kms_helper is loaded because of the module dependency, but fbcon isn't loaded leaving the console unusable. Since fbcon is required and there isn't an explicit module dependency, request the module to be loaded from drm_kms_helper.
Signed-off-by: David Fries david@fries.net Cc: David Airlie airlied@linux.ie Cc: dri-devel@lists.freedesktop.org --- The last patch had a typo 'namue', mental reminder, test again after running checkpatch.pl.
This solves compiling CONFIG_FB=m and being left with a blank screen because the radeon module is automatically loaded, but fbcon isn't. If radeon had to be manually loaded, then it would be the user's fault for not loading fbcon as well, but as radeon is being loaded automatically, there isn't much a user can do from console to even fix it. More bug details from here, https://bugzilla.kernel.org/show_bug.cgi?id=16221
Does this look like a reasonable solution? Should it bother checking find_module first?
drivers/gpu/drm/drm_fb_helper.c | 21 +++++++++++++++++++++ 1 files changed, 21 insertions(+), 0 deletions(-)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index d2849e4..41e3c3c 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -1530,3 +1530,24 @@ bool drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper) } EXPORT_SYMBOL(drm_fb_helper_hotplug_event);
+/* The Kconfig DRM_KMS_HELPER selects FRAMEBUFFER_CONSOLE (if !EMBEDDED) + * but the module doesn't depend on any fb console symbols. At least + * attempt to load fbcon to avoid leaving the system without a usable console. + */ +#if defined(CONFIG_FRAMEBUFFER_CONSOLE_MODULE) && !defined(CONFIG_EMBEDDED) +static int __init drm_fb_helper_modinit(void) +{ + const char *name = "fbcon"; + struct module *fbcon; + + mutex_lock(&module_mutex); + fbcon = find_module(name); + mutex_unlock(&module_mutex); + + if (!fbcon) + request_module_nowait(name); + return 0; +} + +module_init(drm_fb_helper_modinit); +#endif