Hey,
On 22 January 2016 at 07:41, Daniel Vetter daniel@ffwll.ch wrote:
On Thu, Jan 21, 2016 at 7:09 PM, Carlos Palminha CARLOS.PALMINHA@synopsys.com wrote:
i made some progress in identifying the issue... When my driver calls drm_fb_helper_initial_config it seems DRM blocks waiting for register_framebuffer to return. The sequence is drm_fb_helper_initial_config->drm_fb_helper_single_fb_probe->register_framebuffer.
Its strange because register_framebuffer function is just a mutex around do_register_framebuffer.
Any clue?!
Ah, the curse of console_lock. drm_fb_helper_initial_config also does the initial modeset if you have fbcon enabled. But because of locking stupidity we must do _all_ that code (which means pretty much your entire driver) under the console_lock, which means no log output until console_unlock. Not even on serial port.
https://patchwork.freedesktop.org/patch/57951/ is the usual hack to use to get rid of console_lock while booting, so that you can see where your driver crashes. I guess we should explain this in the kerneldoc ...
Didn't spot this at the time, but that should probably quash the WARN_ON_CONSOLE_UNLOCKED warnings as well ...
Cheers, Dan