[PATCH 07/22] drm/tegra: Remove module ownership from the tegra_fb_ops

[Thierry Reding]

On Tue, May 23, 2017 at 03:14:22AM +0300, Dmitry Osipenko wrote:
> The framebuffers console fbcon_startup() increments the tegra_drm module
> 'use' refcount via try_module_get(), causing an interlock of the DRM subsys
> and the tegra_drm modules. In result, the tegra_drm module can't be unloaded
> using rmmod.
> 
> Signed-off-by: Dmitry Osipenko <digetx at gmail.com>
> ---
>  drivers/gpu/drm/tegra/fb.c | 1 -
>  1 file changed, 1 deletion(-)

That's done on purpose because otherwise you could just rip out the
driver from under the framebuffer emulation and things would crash.

My understanding is that the right way to unload a module is to unbind
the driver first (which will cause the framebuffer to be removed and
hence the reference to be dropped) before the rmmod.

Thierry
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